WO2002013257A2 - Semiconductor switch element comprising two control electrodes, which can be controlled by means of field effect - Google Patents

Abstract

The invention relates to a semiconductor device which can be controlled by means of a field effect. Said device contains a semiconductor body (100) comprising a doped first and second contact area (20, 22, 24, 30) to which connecting electrodes (90, 92) for applying power supply potential are connected. A first control electrode (40, 42, 44; 48, 49) is insulated in relation to the semiconductor body (100; 200) and can be connected to a first control potential. A second control electrode (60, 62, 64; 66, 68; 67, 69; 61, 63) is arranged adjacently in relation to the first control electrode (40, 42, 44; 48, 49). Said second control electrode is arranged in the semiconductor body in an insulated manner and can be connected to a second control potential.

Description

Semiconductor switching element with two control electrodes which can be controlled by means of a field effect

The present invention relates to a semiconductor component which can be controlled by means of a field effect, in particular a field effect transistor (FET).

The basic structure of conventional field effect transistors is described, for example, in Stengl / Tihanyi: "Power MOSFET Practice", Pflaum Verlag, Munich, 1992 on pages 29 to 33. Thereafter, conventional FETs have a first connection electrode (source electrode) which is connected to a first connection zone (source zone) of a semiconductor body, and a second connection electrode (drain electrode) which is connected to a second connection zone of the semiconductor body. To control a conductive channel between the first and second connection electrodes, or the first and second connection zones, in the semiconductor body, a control electrode (gate electrode) is provided which is insulated from the semiconductor body and which can be connected to a control potential. The control electrode can be arranged on a surface of the semiconductor body or can extend into the semiconductor body in the case of so-called trench FETs.

In so-called self-blocking FET, a channel zone that is doped complementarily to the source and drain zone is arranged between these two zones. The gate electrode is arranged adjacent to the channel zone and serves to create a conductive channel in the channel zone when a drive potential is applied, in order to enable a current flow in the semiconductor body when a voltage is applied between the drain and source electrodes.

With self-conducting FET, there is usually no complementarily doped channel zone. The task of the gate electrode in these FETs is a normally conductive channel between see drain and source electrodes pinch off by applying a drive potential to the gate electrode in order to prevent current flow between the source and drain electrodes when a supply voltage is present between these electrodes.

For many applications, the aim is for the FET to have a low switch-on resistance and a high dielectric strength, or a high breakdown voltage. The switch-on resistance is defined as the quotient of the voltage between the drain and source electrodes and the drain current flowing between these electrodes. The breakdown voltage is the drain-source voltage at which a normally-off FET breaks down when the gate is not driven.

The breakdown voltage can be increased by a thicker insulation layer between the gate electrode and the semiconductor body. However, this measure is at the expense of. On resistance and increases the value of a parasitic capacitance between the gate electrode and the drain electrode. The increase in this capacity increases the switching losses of the FET at high switching frequencies.

To increase the breakdown voltage, it is also known to form the drain zone from a more heavily doped first zone adjacent to the drain electrode and a less heavily doped second zone which extends between the first zone and the channel zone. The dielectric strength is largely determined by the doping concentration and the dimension of the second zone in the direction of the current flow. However, the on-resistance increases with decreasing doping of the second zone and with increasing dimension of the second zone.

From the article "Dummy Gated Radio Frequency VDMOSFET with

High Breakdown Voltage and Low Feedback Capacitance "by Shuming Xu et al., IEEE ISPSD 2000, pages 385 to 388, it is known to arrange a further electrode above a surface of a semiconductor body in addition to a gate electrode in a VDMOSFET. This procedure takes up a lot of space and is disadvantageous in view of the fact that only limited space is available on the surface of the semiconductor body.

The aim of the present invention is to provide a semiconductor component which can be controlled by means of a field effect and in which a high breakdown voltage can be achieved with a low on-resistance or with low switching losses and which can also be realized in a space-saving manner.

This goal is achieved by a semiconductor arrangement according to the features of claim 1.

According to this, the semiconductor arrangement has a semiconductor body with a doped first connection zone to which a first connection electrode is connected and with a second connection zone to which a second connection electrode is connected. The semiconductor arrangement furthermore has a first control electrode, which is insulated from the semiconductor body by a first insulation layer and which can be connected to a first control potential. The first control electrode serves to control a conductive channel between the first and second connection terminals and is preferably formed adjacent to the first connection zone.

In addition, the semiconductor component according to the invention has a second control electrode arranged adjacent to the first electrode, which is insulated by a second insulation layer in which the semiconductor body is arranged and which can be connected to a second control potential.

The second electrode, which is preferably completely formed in the second connection zone, serves the first "Shield" the control electrode when a supply voltage is present between the connection electrodes or the connection zones, ie it reduces a field strength acting on the first insulation layer of the first control electrode. As a result, in the semiconductor component according to the invention, the first insulation layer can be reduced compared to conventional semiconductor components of this type with the same dielectric strength. On the one hand, this reduces the on-resistance and, on the other hand, the values of parasitic capacitances between the first control electrode and the second connection zone (gate-drain electrode), which leads to lower switching losses. Since in the component according to the invention the voltage between the first and second connection electrodes largely drops in the area of the second control electrode, the doping of the second connection zone can be increased compared to conventional FET without stressing the insulation layer of the first control electrode with a higher field strength. This leads to a further reduction in the on-resistance.

Advantageous embodiments of the invention are the subject of the dependent claims.

According to one embodiment of the invention, it is provided that the thickness of the first insulation layer is less than the thickness of the second insulation layer. As mentioned, the switching losses of the semiconductor component according to the invention are influenced by the thickness of the first insulation layer, the first insulation layer being as thin as possible in order to minimize these switching losses.

The first connection zone and the second control electrode are preferably connected to a common potential. In this embodiment, only a common potential has to be provided for the second control electrode and the first connection zone, as a result of which the wiring outlay in the semiconductor component is reduced. According to one embodiment of the invention, it is provided that the second connection zone has a first zone adjoining the second connection electrode and a second zone adjoining the first zone, the second zone preferably being less doped than the first zone. To produce an IGBT (Insulated Gate Bipolar Transistor), the first zone and the second zone are complementarily doped, while they are of the same conductivity type for producing a field effect transistor.

The present invention, in particular the provision of a second control electrode adjacent to the first control electrode, can be used both for normally-off field-effect transistors and for normally-on field-effect transistors.

In the case of normally-off field-effect transistors, a channel zone is provided which is doped to complement the first and second connection zones and which is formed between the first connection zone and the second connection zone or the second zone of the second connection zone. The first control electrode extends adjacent to the channel zone from the first connection zone to the second connection zone, in order to produce a conductive channel in the channel zone when a control potential is applied to the first control electrode.

In one embodiment of the invention it is provided that the first control electrode and the second control electrode are arranged one above the other in the vertical direction of the semiconductor body. This arrangement is used in particular in the case of vertical semiconductor components in which the first connection electrode is arranged on a front side of the semiconductor body and in which the second connection electrode is arranged on a rear side of the semiconductor body, where in which the current-carrying path extends through the semiconductor body in the vertical direction.

The first and second control electrodes are preferably arranged separated by an insulation layer in a common trench which extends in the vertical direction into the semiconductor body. This arrangement enables the second control electrode to be produced in an uncomplicated manner within the scope of known processes for producing field-effect-controlled semiconductor components.

However, even in the case of semiconductor components in a vertical construction, there is the possibility of arranging the first and the second control electrodes next to one another in the lateral direction of the semiconductor body. The first and second electrodes can also be arranged next to one another in a common trench, the two electrodes being separated by an insulation layer and the second electrode preferably being longer than the first electrode in the vertical direction of the semiconductor body.

According to a further embodiment, it is provided that a doped zone is formed in a transition region of the semiconductor body between the first and second control electrodes and is doped complementarily to the surrounding semiconductor region.

The present invention furthermore relates to a method for producing a semiconductor component according to the invention.

The present invention is described in more detail below with reference to exemplary embodiments in figures

Figure 1 shows a semiconductor device according to the invention according to a first embodiment of the invention in a side view in cross section. FIG. 2 shows a semiconductor arrangement according to FIG. 1 in a top view of the sectional plane AA ¹ shown in FIG. ¹ .

FIG. 3 shows a semiconductor arrangement according to the invention in accordance with a further embodiment of the invention in a lateral sectional illustration.

FIG. 4 shows a self-conducting semiconductor arrangement according to the invention in a lateral representation in cross section.

FIG. 5 shows a further embodiment of a semiconductor arrangement according to the invention in a lateral view

Sectional view.

FIG. 6 shows a semiconductor arrangement according to the invention, in which a first and a second control electrode are arranged next to one another in a common trench.

FIG. 7 shows a semiconductor arrangement according to the invention with first and second control electrodes arranged next to one another.

FIG. 8 shows an electrical equivalent circuit diagram of the semiconductor arrangement according to the invention.

Unless otherwise stated, the same reference symbols in the figures denote the same parts and areas with the same meaning. The present invention is illustrated in the following exemplary embodiments with the aid of an n-conducting field effect transistor (FET). The explanations naturally also apply to p-type semiconductor components, in which case n-type zones have to be replaced by p-type zones, and vice versa. The source zone of an FET can be ω ω M t μ-

LΠ o LΠ o LΠ O σt

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3 • μ- ti H- H- J ΪD 0 Φ Ω i 03 0 Φ CQ 0 li φ t H Φ 0 iQ CQ 0 rt tr α rr CQ ω ft ω μ- μ- IQ? Φ tr rr μ- Ω φ J Φ 0 J li φ. rt φ t- ¹ t Φ ö Ω o Φ o 0 0 03 ω 03 Φ μ- rt t μ- 0 -— ^• 0 = Φ μ- 0 CD li Φ Φ

Φ H- t 0 H tr t-> t 1 1 tr 0 Φ V Φ 03 Φ 0 03 l ii rt 0 Ω N μ-

H- P •. D- PJ Φ 0 * - m tsi Φ 0 μ- t μ- rt 0 φ LQ ISJ • Hl rr ii t ^ Φ CQ $ 0 rr Φ H- 0 H- φ H- ¹ o μ- ü rt rr 0 • > 03 Φ o φ μ- Φ Di 0 li N rt Φ Φ

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? 3 - Pi N φ φ φ rt μ- 1 H rt r φ Ω 0 03 t μ> 0 0 0 rt Φ LQ Φ Φ

0 = 0 0 n HH ⁾ φ o 0 = μ- tr rt ito 0 Φ LQ • 0 rt li 03 ti D * 0 ⁾ 0 PJ 03 CQ 0 o I- ¹ 0> PJ ü 0 μ- Φ Φ * «! o ⁽ Q Φ rt

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Φ 0 ortt ü φ P. 0 1 I- ¹ ii o li tr rt 3 0 0 ü μ- 0 μ- Φ 03 I- * i IQ N 0 t Φ CQ Di tr 1 tr o li 0 03 ≤ φ ffi IQ iQ to 0 0 • N 0 φ CQ 0 Pi H- 0 φ ω i Ω 0 Φ ti I- ¹ D ⁾ Di Φ 0 tr 03 0 μ- Di PJ Φ • LQ O 03

H- tr 0 0 Φ l o tr rt 0 0 Φ Φ 0 Φ μ- Di Φ Φ tr 0 φ 03 μ- CQ 0 0 03

3 Φ Φ CQ H -> H- 0 μ- ii hh rt Φ μ- Φ φ 3 tr rt H 03 Hl 0 Φ N

0 ⁾ H-LQ. _o α * Φ μ- Φ tr ¹ φ rt Q VD φ Φ μ- \ -> Φ rt 0 LQ o

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0 ⁾ P * φ 01 - rt μ- 0 ii IQ N3 • Ö ii t t-> 0 € Φ Φ Φ φ PJ 0 lO DÖ μ- μ-

0 H- rr ti H- 0 0 03 CQ t Φ 03 rt Φ φ 1 Φ ü ii 0 LQ 0 03 Φ φ φ

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• Pi rt- 01 Φ φ NS i 1 ⁾ 0 0 Φ φ i P): Φ tr td tr CQ tr Ξ rr rt li μ- Φ 0

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Φ φ 03 Φ μ- 0 H & μ- IQ 0 = rt H 0 Φ 0 O 0 μ- Φ

03 <£> rt -. 0 0 φ tr φ 03 • n UD 03 t 03 0 03 03 & α Φ rt Φ ti> ^• ö N H- μ- 0 J ii ii

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H- Ω CQ h- ⁴ H- PJ H μ- φ μ- p ⁾ 0 rt • 0 Di 0 _^ 0 Φ Φ ^ rt 0 Φ 0

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μ- μ- rt 0 ii μ- l— * μ- * 03 N LQ Φ tr Φ 0 φ IQ - Di φ Φ φ o - P ⁾ 3 φ 0 φ μ- * tr tr tr Φ. 0 CQ (7t ⁾ μ- Φ H * Φ t- * ii ii rr φ <! φ 0 μ-

Φ φ 03 03 Cd 0 φ 0 Φ Φ Ω 03 Φ LΠ rt J cn rr μ- O Td 3 Φ Φ ü 0 rt rr ii oo t 03 μ- tr rt Φ i rt 0 rt co Φ 0 ü μ- ü LQ

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0 tr μ- Φ rt 0 Φ 0 0 H rt tr CQ 0 μ- tr rt 0 3 LQ 3 φ Di

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Φ 03 co φ? Φ

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3 N N tr li -≤ iQ PJ Φ μ- 0 Di 0 ii rt 0 03 rt »ü ~ Φ

PJ = 0 -s- Φ μ- IQ φ φ 0 tr 0 0 Φ 0 Pi 03 PJ φ φ cn 03 t> 3 Φ ti Φ H li 0 rt Pi LQ ii i Pi rr -j 0 tr 01 P ⁾ 03 T . o φ μ- 03 i 03 Φ Di IQ Φ 0 P. 03 li Φ LΠ φ rr μ- 0 ^• »

0 tr rt rt rr Φ 03 0 rt φ LQ ω N IQ 0 H Φ rr 0 rt 0

rr J 03 iQ μ- PJ rr 0 1X1 K PJ= li μ- rt rr Φ < •* rr Hi Pi rt - Φ μ** Φ Td Td μ- rt 03 Φ Φ PJ crS Ω rt Φ Φ tQ Φ Φ Φ 0= μ- μ- 0 tr ü φ Φ tr Φ Ω 0 . I—^* Φ Φ Φ μ- 0 φ ii 0 ü φ PJ σ\ Φ μ** Φ rt 0 tr Φ rt o= tr 0 1 0 Φ 0 tr Ω Φ 3 I—¹ Φ ü φ 0 Di φ μ- 0 Φ I-¹ tSJ rt li 0= μ- tr ü μ- tsi ^•P μ- φ Φ 03 tu ISI i 0 0 φ td 0 cn Φ tr 0 Φ "P LQ s^* I-* 0 O rt < Hl Hl μ- p d φ Φ μ- PJ 0 rr μ- μ* Φ O Φ μ- 0 rtΦ φ Φ Φ Φ rt 0 ^• P Φ 3 φ 0 • Φ H 0 Φ Pi Φ 03 tu 03 0 0 ii μ- ¹ io N 3 0 φ 03 cn iQ 03 0 0

rr J 03 iQ μ- PJ rr 0 1X1 K PJ = li μ- rt rr Φ <• * rr Hi Pi rt - Φ μ ** Φ Td Td μ- rt 03 Φ Φ PJ crS Ω rt Φ Φ tQ Φ Φ Φ 0 = μ- μ- 0 tr ü φ Φ tr Φ Ω 0. I— ^* Φ Φ Φ μ- 0 φ ii 0 ü φ PJ σ \ Φ μ ** Φ rt 0 tr Φ rt o = tr 0 1 0 Φ 0 tr Ω Φ 3 I— ¹ Φ ü φ 0 Di φ μ- 0 Φ I- ¹ tSJ rt li 0 = μ- tr ü μ- tsi ^• P μ- φ Φ 03 tu ISI i 0 0 φ td 0 cn Φ tr 0 Φ "P LQ s ^* I- * 0 O rt <Hl Hl μ- pd φ Φ μ- PJ 0 rr μ- μ * Φ O Φ μ- 0 rt

Φ Φ Hi Hi Ω ii μ- Φ 0 N rt Φ Φ 03 φ Ü φ Pi rr ⁾ μ- Φ Di Φ li ii Φ Φ tr tr 03 0 Φ tr 0 0 rt ^ rr μ- Φ 0 rt LQ 0

PJ CQ? * PJ Φ 0 ü Φ • »rr Pi φ 0 03 Φ Φ Di rr

0 rt rt rt Pi φ rt 0 0 σ ii? Φ to li li Φ 0 r LQ 0 0 μ- μ-

0 pι = rt rt μ- N Di PJ φ 0 = μ- o Φ μ- 0 3 0 N μ- Φ • φ pi

H 0 i li 03 rr 03 μ- Di pi li r - 0 Pi Pi s; ⁾ tr cn i P. JJ Φ Ω 0> 0 l- ^{1 •} P Φ Φ Φ tn Φ μ- μ- rt cn

0 0 0 0 Jti li tr 0 li μ- Φ ii to? φ 0 PJ S μ- Φ 0 μ-

0 μ- 03 03 φ PJ J Di 03 Ω 03 li tr to rt 0 Φ rt μ- P. 0 0 03

0 ß μ- μ- μ- 0 μ- Φ rt tr μ- PJ - li rt Φ tr H Φ 03 Φ Φ i rt Q 03 03 tr 0 rt ü Φ - φ μ- 0 0 oo Ω 0 rr rt ii Ω - rr rt Φ ü tr 03 0 • io Φ tso ^• P Φ tr • Φ φ μ- φ 0 o 0 D. μ- φ φ Pi φ o h- * φ Φ ti μ- Φ cn φ l- ¹ 1 ω

0 ii ti ü CQ 0 H- * ü PJ 0 Φ 0 _! Φ Φ rr rt μ- N φ Cd 0

03 03 Ω 0 D. tr • P 03 3 3 03 Ω to Φ 3 Φ 0 0 .V

-T] Td tr 0 Φ 0 03 0 = φ μ- Φ: tr - ii μ- 0 φ 3 rt Φ Di μ- 0 m 1-3 PJ LQ Di 0 rt 0 LQ 0 0 o Φ X rt Φ • i ? PJ Q 0 to μ-. Φ Φ PJ 3 rt Di * -; 0 φ 0 = rt ti LQ> 0 rt 03

- rt ii>. 0 I- * μ- 03 p. φ ti Φ Φ φ 0 P. li 03 rt 0 0 φ r 3 Ω - ι-3> Φ • P h- ¹ 3 Φ 0

OD μ- • s 0 0 μ- μ- μ- Φ 0 = tr φ to! ü w φ 03 φ φ Φ 0 Di D.

O O Di IQ P CQ PJ IQ 03 $ μ- - o = ii? μ- LQ Φ μ-

N 0 tr Φ μ ^{* 1} ISI rr 0 s! 0 Φ rt 0 Φ σ. Φ

03 Φ Φ Φ Di Φ Φ μ- tr φ φ 0 μ> μ- li 03 0 o vo μ- 3 μ- μ- μ- Φ PJ Ω <Φ Φ φ μ- φ o 0 0 J - o N

03 Φ 0 0 0 0 PJ μ- * tr μ- μ- μ- - 01 0 o Φ P. 3 PJ • ≤

Ω μ- Di φ Φ LQ 0 φ 03 φ 0 Φ li Φ φ 0 cn J Φ tr tn μ- 03 03 T Φ LQ 0 rt φ φ Lπ μ- 0 co 0 μ-

Φ φ φ μ- 1 Φ Φ 03 ii os; ≤ 03 Φ ^• • Hl rt

φ φ 1 0 0 0 03 1 1 μ- μ- 0 μ- Φ φ 0

φ φ 1 0 0

> ω co to μ> μ-

LΠ o LΠ o LΠ o Lπ

Φ μ-

0

Φ

3 φ left

03

0 fi

IQ

0

0

LQ

03

• P

Location

Φ

0 rr μ- pi

<μ ¹

0

0 i

Φ μ-

0

Φ

3 do

Φ

N

0

LQ

CQ

^• P

0 rr

Φ

0 rt μ-

Pi μ-

Ω

≥i α

electrode 60, 62, 64 for a high voltage drop in the region of the drain zone, so that the second zone 302 can be doped higher.

The semiconductor device according to the invention appears to the outside like a field effect transistor, i.e. there is a first connection terminal 90, S which corresponds to the source electrode, there is a second connection terminal 92, D which corresponds to the drain electrode and there is a first control terminal G which corresponds to the gate electrode. The switching behavior of the semiconductor component according to the invention also corresponds to that of a field effect transistor, in particular a MOS-FET, the semiconductor component according to the invention having a lower switch-on resistance and lower switching losses than conventional MOS-FET.

FIG. 3 shows a further exemplary embodiment of a semiconductor component according to the invention in a lateral sectional view, the structure of which essentially corresponds to that of the semiconductor component according to FIG. 1. 1, the first control electrode 40, 42, 44 only just extends into the second connection zone 30, the first connection electrode 40 (reference symbols for the other cells are omitted for reasons of clarity) in the exemplary embodiment according to FIG 3 far into the second connection zone 30. In the exemplary embodiment according to FIG. 3, the second connection zone 30 consists of a heavily doped first zone 301, which connects to the second connection electrode 92. Adjacent to the first zone is an n-doped zone 303, which is preferably embodied as an epitaxial layer and to which a further n-doped zone 304 adjoins in the vertical direction of the semiconductor body 100 and which adjoins the regions between those in the lateral direction lying first

Fills control electrodes 40 and the second control electrodes 60 lying next to one another in the lateral direction. A further exemplary embodiment of the semiconductor component according to the invention is shown in a side sectional illustration in FIG. 4. In this embodiment, second electrodes 66, 68 are arranged at a distance from the first electrodes 40, 42 in the vertical direction of the semiconductor body and have a greater extent in the lateral direction of the semiconductor body than the first control electrodes 40, 42. Regions of the second connection zone 30 are preferred , which extend between the first control electrodes 40, 42 and the second control electrodes 66, 68, p-doped, as indicated in FIG. 4 by the areas 310, 312 shown in broken lines. The second control electrodes 66, 68 are completely surrounded by insulation layers 76, 78, which are preferably thicker than the insulation layers 50, 52 of the first control electrodes. The distances between the second and second control electrodes 66, 68 and thus the dimensions of the conductive channel between the first and second connection electrodes 90, 92 can be influenced by the lateral extent of the second control electrodes 66, 68. It applies that the field strength that ultimately acts on the thinner insulation layer 50, 52 of the first control electrodes 40, 42 is lower, the smaller the distances between the second control electrodes 66, 68. The second control electrodes 66, 68 act in the manner of a field plate grid on which the voltage drop is greater the finer the grid, ie the closer the individual electrodes 66, 68 are to one another. In this embodiment, the second connection zone 30 can also consist of a first zone 301 and a second zone 303, 304, which in turn can have an eptaxia layer 303.

In an embodiment not shown in FIG. 4, there is also the possibility that the second electrodes extend into the heavily doped first zone 301 of the second connection zone 30. 5 shows a further embodiment of the semiconductor component according to the invention, in which first control electrodes 48, 49 and second control electrodes 67, 69 are arranged next to one another in a common trench 110, 112, 114 of the semiconductor body 100, the first and second control electrodes 48 , 68; 49, 69 are each separated from one another and from the semiconductor body 100 by an insulation layer 77, 79. In the exemplary embodiment according to FIG. 5, the second control electrode 67, 69 extends in the vertical direction of the semiconductor body 100 further into the second connection zone 30 than the first connection electrode 48, 49, which only just up to the second connection zone 30, surrounded by the insulation layer 77. The thickness of the insulation layer that separates the first control electrodes 48, 49 from the semiconductor body is thinner than the thickness of the insulation layer that separates the second electrode 67, 69 from the semiconductor body 100.

The first control electrodes 48, 49 and the second control electrodes 67, 69 can be plate-shaped, two first control electrodes 48 each flanking a second control electrode 67. The first control electrodes 48 can also completely surround the second control electrode 67 in the upper region. The first control electrodes 48, 49 can be connected or connected to a common first control potential, and the second control electrodes 67, 69 can be connected or connected to a common control potential.

While in the previously described embodiments a channel zone 80, which is doped complementarily to the first and second connection zones 20, 22, 24, 30, is always formed between the first connection zone 20, 22, 24 and the second connection zone 30, FIG. 6 shows an exemplary embodiment of a channel - Finding a semiconductor device in which the first connection zone 30 directly reaches up to the second connection zone 20, 24. The second connection zone 30 exists from an n-doped first zone 301, which is formed adjacent to the second connection electrode 92 and from an n-doped second zone 306, which is arranged between the first zone 301 and the second connection zone 20, 24. The semiconductor arrangement shown in FIG. 6 is self-conducting, ie when a supply voltage is applied between the first connection terminal 90, S and the second connection terminal 92, D, a current flows through the semiconductor body 100 in the vertical direction when the first control electrode 40, 42 nem reference potential. If a drive potential is applied to the first control electrode 40, 42, G, which leads to a negative voltage between the gate electrode G and the source electrode 90, S, the conductive channel between the first control electrodes 40, 42 is pinched off, as a result of which the potential in the second zone 306 in the lower region of the first control electrodes 40, 42 increases. As a result, the conductive channels between the control electrodes 60, 62, which are at a fixed control potential, preferably the potential of the first connection electrode 90, are also pinched off and the semiconductor arrangement is blocked. As in the previously described embodiments, the insulation layer 70, 72 of the second control electrodes 60, 62 is thicker than the insulation layer around the first control electrodes 40, 42.

7 shows a further embodiment of the semiconductor component according to the invention, in which a first control electrode 40, 42 and a second control electrode 61, 63 are arranged next to one another in the lateral direction of the semiconductor body, the first control electrodes 40, 42 being formed by first insulation layers 50, 52 and the second control electrodes 61, 63 are each surrounded by second insulation layers 71, 73. The first control electrodes 40, 42 are arranged adjacent to first connection zones 20, 22, which are connected to a first connection electrode 90, S, which is arranged on a front side of the semiconductor body 100. A second connection electrode 92, D is arranged on a rear side of the semiconductor body 100. The 7 serves to contact a second connection zone 30, which in the exemplary embodiment according to FIG. 7 has a p-doped first zone 307 following the second connection electrode 92, D and an n-doped second zone 302 following the first Zone 307 has. Between the second connection zone 30, or the second zone 302, and the first connection zone 20, 22, a p-conductive channel zone 80 is formed, along which the first control electrodes 40, 42 extend from the front of the semiconductor body 100 into the extend first connection zone 30. Further p-doped zones 85, 86, 87 are formed between the first and second control electrodes 40, 42, 61, 63 above the drain zone 30 and below the source electrode 90, and are insulated from the source electrode 90 by insulating layers 185, 186, 187, 188 are isolated.

7 functions due to the complementarily doped first and second zones

302, 307 of the second connection zone or the drain zone, in the manner of an IGBT (Insulated Gate Bipolar Transistor). In this embodiment as well, the second scattering electrodes 61, 63 shield the first control electrodes and prevent large field strengths on the first insulation layers 50, 52. The p-doped zones 85, 86, 87, 88 between the first and second control electrodes 40, 42 , 61, 63, which are not connected to the source electrode 90, are at the potential of the upper part of the second zone 302, which changes with the potential at the drain electrode 92. The areas where the control electrodes 40, 42 and the p-doped zones overlap (gate-drain overlap) contribute to the gate-drain capacitance. The electrodes 61, 63 shield the first control electrodes 40, 42 from the drain potential, so that a displacement current, which is caused by a change in the drain potential, is partially taken over by the second control electrodes 61, 63. The invention further relates to a method for producing a semiconductor component according to the invention, which is to be explained with reference to FIG. ¹ FIG. ¹ .

In a first method step, a semiconductor body 100 is provided, which has a first connection zone 20, 22, 24 of a first conductivity type n, a second connection zone 30 of the first conductivity type n and a channel zone 80 arranged between the first and second connection zones 20, 22, 24, 30 has a second conduction type p. In a next method step, starting from a front side 102 of the semiconductor body 100, at least one trench 110, 112, 114 is produced in the semiconductor body 100, the trench 110, 112, 114 passing through the first connection zone 20, 22, 24 and through the channel zone 80 extends into the second connection zone 30.

Then an insulation layer, which forms the later first and second insulation layers 50, 52, 54, 70, 72, 74, is applied to side surfaces of the trenches 110, 112, 114. Then, to form the second control electrodes 60, 62, 64, a first layer of an electrode material is introduced into the trenches 110, 112, 114, which partially fills the trenches. The height of the first layer preferably does not reach into the channel zone 80, as a result of which the second control electrodes 60, 62, 64 are completely formed in the second connection zone 30.

A further insulation layer is then applied to the first layer of electrode material in the trenches, this further insulation layer and the insulation layer already applied to the side walls in the region of the second electrodes forming the second insulation layers 70, 72, 74 of the second control electrodes 60, 62, 64 ,

In a next step, a further layer of electrode material is placed in the electrodes to form the first control electrodes Trenches 110, 112, 114 deposited, which fills the trenches 11, 112, 114 preferably almost completely.

In order to make the first insulation layer 50, 52, 54 thinner than the second insulation layer 70, 72, 74, it is provided in one embodiment of the production method that the applied to the side walls of the trenches 110, 112, 114 after the production of the second electrodes 60 , 62, 64 exposed insulation layer is made thinner. The insulation layer preferably consists of a semiconductor oxide; the thickness of the oxide layer is preferably reduced by so-called "oxide polishing". It is also possible to remove the first insulation layer after producing the second electrodes 60, 62, 64 up to the height of the second electrodes 60, 62, 64, for example by etching, and then to apply a further thinner insulation layer to the side walls of the trenches ,

After the production of the first electrodes 40, 42, 44, a further insulation layer on the first electrodes 40,

42, 44, which serves to isolate the first electrodes 40, 42, 44 from the first connection electrode 90, which is applied to the front side 102 of the semiconductor body 100 in a next method step. In addition, a second connection electrode is applied to a rear side of the semiconductor body in order to arrive at the arrangement according to FIG. 1.

Alternatively, the second connection zones 20, 22, 24 can also only be produced after the trenches 110, 112, 114 have been produced by doping the surface of the semiconductor body, after the electrodes 40, 42, 44, 60, 62, 64 in the trenches 110, 112, 114 are made.

In order to be able to contact the first and second electrodes 40, 42, 44, 60, 62, 64 for applying the control potentials, connections are to be provided which are on one of the surfaces of the Semiconductor body 100 are accessible. For the first as well as for the second electrodes 40, 42, 44, 60, 62, 64 there is the possibility for this purpose, starting from the front surface 102 of the semiconductor body, to make contact holes up to the respective electrodes, which the electrodes 40, 42, 44; 60, 62, 64 meet in one place and in which connections can be made isolated from the surrounding material. It is also possible to leave recesses above the lower second electrodes 60, 62, 64 in the manufacture of the first electrodes, in which openings connections can then be made.

The electrodes can also be designed such that they are exposed at the edges of the cell field on the surface in order to be contacted.

The connections for both the first and for the second electrodes can, as shown in FIG. 2, be designed as a common plate, one plate contacting all first electrodes and another plate contacting all second electrodes, and both plates extend in the vertical direction to the front of the semiconductor body and are each surrounded by an insulation layer 75.

Claims

claims 1. A semiconductor arrangement which can be controlled by means of a field effect and has the following features: - A semiconductor body (100) with a doped first connection zone (20, 22, 24) and a doped second connection zone (30); - a first connection electrode (90) connected to the first connection zone (20, 22, 24) for applying a first supply potential and a second connection electrode (92) connected to the second connection zone (30; 32, 34) for applying a second supply potential; - A first control electrode (40, 42, 44; 48, 49) which is insulated from the semiconductor body (100; - 200) by a first insulation layer (50, 52, 54; 77, 79) and which can be connected to a first control potential ; marked by - A second control electrode (60, 62, 64; 66, 68; 67, 69; 61, 63) which is arranged adjacent to the first electrode (40, 42, 44; 48, 49) and which is formed by a second insulation layer (70, 72 , 74; 76, 78; 77, 79; 71, 73; 75) is insulated in the semiconductor body (100) and can be connected to a second control potential. 2. The semiconductor arrangement according to claim 1, wherein the thickness of the first insulation layer (50, 52, 54) is less than the thickness of the second insulation layer (70, 72, 74; 76, 78). 3. Semiconductor arrangement according to claim 1 or 2, wherein the first connection zone (20, 22, 24) and the second control electrode (92) are connected to a common potential. 4. Semiconductor arrangement according to one of the preceding claims, in which the second connection zone (30) is a first zone (301; 307) adjoining the second connection electrode (92) and a second zone (302; 303, 304). 5. The semiconductor device according to claim 4, wherein the first zone (301) and the second zone (302; 303, 304) are of a first conductivity type (s). 6. The semiconductor device as claimed in claim 4, in which the first zone (307) is of a second conductivity type (p) and in which the second zone (302) is of the first conductivity type (n). 7. Semiconductor arrangement according to one of the preceding claims, in which the first zone (301) is more heavily doped than the second zone (302; 302, 304). 8. Semiconductor arrangement according to one of the preceding claims, in which the first connection zone (20, 22, 24) from the first Is a conduction type (n) and in which a channel zone (80) of the second conduction type (p) is formed between the first connection zone (20, 22, 24; 28) and the second connection zone (30), and the insulated first control electrode (40 , 42, 44) adjacent to the channel zone (80; 82) from the first connection zone (20, 22, 24) to the second connection zone (30). 9. Semiconductor arrangement according to one of the preceding claims, in which the second control electrode (60, 62, 64; 66, 68) in the second connection zone (30), preferably the second zone (302; 303, 304) of the second connection zone ( 30) is arranged. 10. Semiconductor arrangement according to one of the preceding claims, wherein the first control electrode (50, 52, 54) and the second control electrode (60, 62, 64; 66, 68) in vertical Direction of the semiconductor body (100) are arranged one above the other. 11. The semiconductor arrangement as claimed in claim 10, in which the first control electrode (40, 42, 44; 48, 49) and the second control electrode (60, 62, 64; 67, 69) are separated by an insulation layer (50, 52, 54, 70) , 72, 74; 77, 79) are arranged in a common trench. 12. Semiconductor arrangement according to one of the preceding claims, in which the first control electrode (40, 42; 48, 49) and the second control electrode (61, 63; 67, 69) are arranged side by side in the lateral direction of the semiconductor body (100). 13. Semiconductor arrangement according to one of the preceding claims, in which the first and second control electrodes (48, 49, 67, 69) are arranged next to one another in a common “trench”, the second electrode (67, 69) in the vertical direction of the semiconductor body (100) is longer than the first electrode (48, 49). 14. The semiconductor arrangement according to claim 13, wherein the first electrode (48, 49) at least partially surrounds the second electrode (67, 69). 15. Semiconductor arrangement according to one of the preceding claims, in which a zone (310, 312) of the second conductivity type (p) is formed in a transition region of the semiconductor body (100) between the first and second control electrodes (40, 42; 66, 68). 16. A method for producing a semiconductor device, which has the following features: - Providing a semiconductor body (100) which has a first connection zone (20, 22, 24) of a first conductivity type (s), ne has a second connection zone (30) of the first conduction type (n) and a channel zone (80) of a second conduction type (p) arranged between the first and second connection zones (20, 22, 24, 30); - Creating at least one trench (110, 112, 114) in the semiconductor body (100), which extends from a front side of the semiconductor body (100) through the first connection zone (20, 22, 24) and the channel zone (80) into the second connection zone (30) extends; - depositing an insulation layer on the side walls of the at least one trench; - Introducing a first electrode material to form a second electrode (60, 62, 64) in the trench (110, 112, 114), which partially fills the trench; - Application of an insulation layer on the first electrode material in the trench; - Introducing a second electrode material into the trench. 17. The method according to claim 16, wherein the insulation layer on the side walls of the trench (110, 112, 114) is made thinner after the introduction of the first electrode material but before the introduction of the second electrode material. 18. The method according to claim 16, wherein the insulation layer on the side walls of the trench (110, 112, 114) after the Introducing the first electrode material is etched back, after which a thinner insulation layer is applied to the side walls of the trench (110, 112, 114). 19. The method of claim 16 or 17, wherein the first connection zone (20, 22, 24), the channel zone (80) and the second Connection zone (30) in the semiconductor body (100) are arranged in layers one above the other. LIST OF REFERENCE NUMBERS 100 semiconductor bodies 102 front side of the semiconductor body 104 Back of the semiconductor body 110, 112, 114 trench 20, 22, 24 first connection zone 30 second connection zone 301 first zone of the second connection zone 302 second zone of the second connection zone 303, 304, 306 second zone of the second connection zone 310, 312 p-doped zones 40, 42, 44 first control electrode 48, 49 first control electrode 50, 52, 54 first insulation layer 60, 62, 64 second control electrode 61, 63 second control electrode 65 second control electrode 651 common plate of the second electrodes 66, 68 second control electrode 67, 69 second control electrode 70, 72, 74 second insulation layer 71, 73 insulation layer 751 insulation layer 76, 78 insulation layer 77, 79 insulation layer 80 channel zone 90 first connection electrode 92 second connection electrode D, Dl, D2 drain connection G, Gl, G2 gate connection GND reference potential n n-doped zone p p-doped zone S, Sl, S2 Source connection TI first transistor T2 second transistor VI supply potential