KR100650115B1 - Nanoelectronic Devices Using Nonlinear Conductivity of Metallic Spiral Thin Films - Google Patents

Abstract

The present invention is the nano-electron using the nonlinear conduction characteristics of the metal spiral thin film using the nonlinear conduction and the change of conduction characteristics according to the relative direction of the external magnetic field and current direction and the rotational direction of the spiral structure in the spiral metal thin film It relates to an element.

According to the present invention, when a voltage is applied to both ends of a thin film made of a spiral structure and a magnetic field is applied from the outside, the resistance value is greatly changed depending on the electric field, the magnetic field, and the relative directionality of the spiral structure. Under the direction of the nanoelectronic device, the resistance value changes greatly depending on the direction of the current. It is similar to a diode. For a given current direction, if the direction of the magnetic field is changed, the resistance value changes relatively. As it can be provided to overcome the physical limitations caused by the miniaturization of nano-sized semiconductor devices.

Description

Nano electronic device using nonlinear conduction characteristics of thin metal spiral thin film {A NANO ELECTRIC DEVICE USING NON-LINEAR CONDUCTIVITY OF SPIRAL METAL FILMS}

1 illustrates a typical metal thin film fabricated in a spiral structure.

2A and 2B are schematic views of a spiral thin film grown with a schematic diagram of the GLAD method.

3 is an electrode formed on top and bottom of the spiral thin film for the implementation of the present invention.

Figure 4 is a schematic diagram of the movement of electrons when the electric and magnetic fields are applied in FIG.

5 is a view showing the non-linear conduction characteristics using the spiral structure in the present invention.

FIG. 6 is a structural diagram in which two spiral structures having different directions from each other are deposited with an electrode therebetween according to the present invention; FIG.

<Description of the symbols for the main parts of the drawings>

10,10a, 10b: metal spiral thin film 20,30,40: electrode

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device using nonlinear conduction characteristics in a metal spiral thin film. In particular, the phenomenon of change in conduction characteristics and its nonlinearity according to the relative direction of the external magnetic field and the current direction and the rotation direction of the spiral structure in a spiral metal thin film The present invention relates to a nanoelectronic device using nonlinear conduction characteristics of a thin metal thin film using conduction phenomena.

Recently, the development of the electronics industry is at the core of price competitiveness and performance improvement due to the miniaturization of devices. The problem is that the physical technology of the semiconductor industry, which is the period of the current semiconductor industry, has been miniaturized at the nanoscale. Is that the limit is emerging.

The fabrication of nanoscale devices is difficult, but even if this problem is overcome, the deterioration of signal-to-noise ratio caused by the small number of carriers carrying signals when the physical properties of the semiconductor devices themselves have nanoscale line widths and generation of heat due to large resistance The problem of cooling due to and low thermal conductivity is indeed a serious problem. In particular, the generation of heat, in turn, means more energy consumption, which is directly related to energy consumption.

In addition, low power consumption is a very important factor in portable devices that are currently developing, and therefore, it is very important to suppress the generation of heat. Therefore, recognizing the importance of developing new devices to replace semiconductors, countries around the world are investing heavily in research into potential new functional devices.

In particular, the development of a device capable of overcoming the problem of miniaturization of a semiconductor device while operating similar to a diode or a transistor, which is the basis of a conventional semiconductor technology, is very important throughout the electronic industry. As it is a source technology, it is in a fierce competition.

On the other hand, in the case of a metal diode, a large number of free electrons, which are inherent in the metal, have a sufficient number of carriers even at a nanoscale line width, and a low resistance value can minimize heat generation and generate high heat. There is an advantage that can be easily outflowed by the thermal conductivity.

However, a device made of metal is considered to be impossible to manufacture a nonlinear diode because the resistance value shows a constant value irrespective of current or voltage due to a linear current-voltage relationship known as Ohm's law.

That is, in order to exhibit nonlinear conductivity such as a diode, the conductivity of the device itself must be nonlinear with respect to voltage or current, and thus it is not possible to utilize the excellent properties of the metal.

Thus, the key is how to make non-conductive the conductivity of metals with good conductive properties after all.

Indeed, the Giant Magnetoresistance (GMR) phenomenon, known as the biggest success story of nanotechnology and already commercialized and widely used as a playhead for hard disks, is also the resistance between two neighboring ferromagnetic layers. It is a device using nonlinearity affected by the relative magnetization direction, and devices such as magnetoresistive random access memory (MRAM), phase change RAM (PRAM), and resistive RAM (RRAM), which are being actively studied as next-generation nonvolatile memories, also have conductivity. The principle of operation is based on the nonlinearity and the rapid change of the device state.

A method of manufacturing a spiral metal thin film has already been applied for a patent (KJ Robbie and MJ Brett, US patent No. 5,866,204 (1999)), and many studies related to the manufacturing of a spiral thin film have been preceded (K Robbie, JC Sit and MJ Brett, J. Vac. Sci. Technol. B. 16, 1115 (1998)).

In particular, as suggested by Azzam (RMA Azzam, Appl. Phys. Lett. 61, 3118 (1992)), optical activity dependent on the chiral direction was observed experimentally in a spiral-shaped thin film and reported to Nature in 1999. Has attracted much attention (K. Robbie, MJ Brett, and A. Lakhtakia, Nature 384, 616 (1996)).

This optical activity is possible because the length scale of the spiral structure is known to have a size similar to the wavelength of light, and many studies on the thin film of the spiral structure have been conducted in relation to the optical activity.

FIG. 1 shows a typical metal thin film fabricated in a spiral structure according to US Pat. No. 5,866,204. The spiral thin film uses a GLAD (GLancing Angle Deposition) method, and a schematic diagram of this deposition method is shown in FIG. 2.

As shown in FIG. 2, when the thin film is deposited, the incident angle α of the vapor vapor to be deposited is set to an angle close to 90 degrees, and the substrate is rotated to have a constant angular velocity, thereby self-swinging the self shadow of the thin film. It is possible to grow a thin film having a spiral structure as shown in Figure 1 by the shadowing effect.

At this time, since the chiral direction of the spiral is determined by the rotation direction of the substrate, it can be easily determined, and the pitch, thickness, and radius of the spiral can be easily controlled as a function of the deposition rate and the rotational angular velocity of the substrate. Is determined.

In the research of Robbie et al., The main concern is optical activity, so the size of the spiral, such as the radius of the spiral structure, is determined to be similar to the wavelength of light. It is possible to manufacture a thin film having a spiral structure having a.

Therefore, methods for overcoming the physical limitations caused by the miniaturization of nanoscale devices of semiconductor devices using the spiral metal thin film have been sought.

The present invention has been made in view of the above, and an object of the present invention is to use a change in conduction characteristics and a nonlinear conduction phenomenon according to the relative direction of the external magnetic field and the current direction and the rotational direction of the spiral structure in a spiral metal thin film. The present invention provides a nanoelectronic device using the nonlinear conduction characteristics of a spiral metal thin film to overcome the physical limitations caused by the miniaturization of nanoscale semiconductor devices by allowing the thin metal thin film to function as a nonlinear device.

The nanoelectronic device using the nonlinear conduction characteristics of the metal spiral thin film according to the present invention for achieving the above object, to form an electrode on the upper and lower portions of the metal thin film of the spiral structure, by applying a voltage to the electrode to form an electric field While applying a magnetic field from the outside it is characterized in that the spiral metal thin film to operate as a device having a non-linear conduction characteristics.

The spiral metal thin film is formed of a magnetic material or a multilayer thin film or superconductor of the magnetic material, and the upper and lower electrodes are a group 3 transition element alloy, such as a ferromagnetic or ferromagnetic alloy, and a rare earth transition metal alloy, or a multilayer of ferromagnetic and nonferromagnetic materials. It is formed of a thin film, the magnetic field is characterized in that the application of a permanent magnet or an electromagnet from the outside of the metal thin film of the spiral structure.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following examples are merely to illustrate the present invention is not limited to the contents of the present invention.

The present invention is based on the conductive properties of a spiral metal thin film manufactured using the GLAD method, and a device capable of performing the function of a nonlinear device such as a diode, which is a semiconductor basic device, and the device having a resistance depending on the direction of an external magnetic field. It is intended to be used as a kind of magnetoresistive element because it is changed.

3 illustrates electrodes 20 and 30 formed on the upper and lower portions of the metal spiral thin film 10 as shown in FIG. 1.

The metal spiral thin film 10 may be made of a magnetic body or a multilayer thin film of a magnetic body, or may be made of a superconductor.

The electrodes 20 and 30 may be a Group 3 transition element alloy such as a ferromagnetic material (Co, Fe, Ni) or an alloy of ferromagnetic material (CoFe, NiFe, etc.) and a rare earth transition metal alloy, or a non-ferromagnetic material (Pd, Pt, Ir). And noble metals such as Cr, Cu, Au, Ag) and alloys thereof, and multilayer thin films.

As such, when the electrodes 20 and 30 are respectively formed on the upper and lower portions of the metal spiral thin film 10, and a voltage is applied, an electric field is generated in the spiral structure.

At this time, a magnetic field is applied externally by using a permanent magnet or an electromagnet or a magnetic field generated by an electrode made of a magnetic layer causes electric charges in a spiral structure to move under a Lorentz force in a space where electric field E and magnetic field B exist simultaneously. do.

The charges in the spiral structure rotate in a plane perpendicular to the magnetic field, where the direction of rotation is determined by the sign of the charge. In addition, depending on the sign of the electric charge, the force is also applied in the direction parallel or antiparallel to the direction of the electric field.

If the charges move without collision, they will move at an equivalent speed by the electric field, but due to various scattering phenomena inside the solid, they will move at a constant speed called the Drift Velocity (v _d ).

Therefore, in the space where the electric field and the magnetic field exist at the same time, the electric charges have the rotational motion perpendicular to the magnetic field and the constant velocity motion in the direction of the electric field. If the electric and magnetic fields are horizontal to each other, the spiral motion as shown in FIG.

Actually, the distribution of electric field inside the spiral is difficult to accurately describe because the electric structure of the spiral is influenced by the specific microstructure of the spiral structure, but the important thing is that the electric and magnetic fields cause the movement of the spiral motion in which charges rotate in one direction.

Therefore, if the rotational direction of the spiral structure and the direction of the spiral motion due to the electric and magnetic fields coincide, and the spiral geometric size is similar to the magnitude of the charge movements, the charges move along the spiral structure so that there is little scattering by the surface of the spiral. do.

On the other hand, when the direction of the spiral structure and the direction of rotation of the electrons do not coincide, the scattering occurs on the surface of the spiral structure because the motion of the spiral structure and the charges do not coincide.

As a result, the effective surface scattering area felt by the charges is changed by the direction of the electric field and the magnetic field, and the rotational direction of the spiral structure. As a result, the resistance of the fixed magnetic field and the spiral structure depends on the direction of the electric field, that is, the direction of the current. The value will change.

In addition, with respect to the direction of the predetermined electric field and the direction of the spiral structure, the magnetoresistive element whose resistance value changes depending on the external magnetic field or the magnetization direction of the magnetic body forming the electrode layer or the magnetization direction of the magnetic body forming the spiral structure can be operated. .

Therefore, as shown in FIG. 5, the operation of the device having the nonlinear conduction characteristic having characteristics similar to those of the diode is possible. That is, FIG. 5 schematically shows the change in conduction characteristics according to the direction of the current and the direction of the magnetic field. As shown in the figure on the right side of FIG. 5, the current-voltage characteristic curve is very different as the voltage changes from the reverse voltage to the forward voltage. It will behave like a diode that changes from a large resistor to a small resistor, and this conducting characteristic will have a small resistance under reverse voltage if the magnetic field is redirected. Also, if you change the direction of the magnetic field under a certain voltage, it will act as a kind of magnetoresistive element whose resistance value changes.

In addition, as shown in FIG. 6, when the inter-electrode 40 is further configured in FIG. 3 and the metal spiral thin films 10a and 10b of different directions are deposited, the three electrodes 20, 30, and 40 are deposited. By adjusting the relative potential difference between the (), since the resistance value between the electrodes 20, 30, 40 is changed, it is possible to adjust the value of the current that can flow in the end.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art various modifications of the present invention without departing from the spirit and scope of the invention described in the claims below Or it may be modified.

As described above, in the present invention, when a voltage is applied to both ends of the metal thin film manufactured in the spiral structure and a magnetic field is applied from the outside, the resistance value is greatly changed according to the relative direction of the electric field, the magnetic field and the spiral structure inside the thin film. This results in a diode-like characteristic in which the resistance value changes greatly depending on the direction of the current under the direction of the given magnetic field, and when the direction of the magnetic field is changed in the given direction of the current, the resistance of the resistance changes relatively. As a result, it is possible to obtain a metal diode or a magnetoresistive element that can overcome the physical limitations caused by the miniaturization of the nano-sized semiconductor devices. In addition, the present invention can be applied to the magnetic sensor element using the magnetoresistance characteristics or the circuit element using the diode characteristics.

Claims (9)

Electrodes are formed on the upper and lower portions of the spiral metal thin film, and a magnetic field is applied from the outside while a voltage is applied to the electrodes to form an electric field so that the metallic thin film of the spiral structure functions as a device having nonlinear conduction characteristics. Nanoelectronic device using the nonlinear conduction characteristics of the metal spiral thin film. The method of claim 1, wherein the spiral metal thin film A nanoelectronic device using the nonlinear conduction characteristics of a metal spiral thin film, which is formed of a magnetic body or a multilayer thin film of a magnetic body. The method of claim 1, wherein the spiral metal thin film Nanoelectronic device using the nonlinear conduction characteristics of the metal spiral thin film, characterized in that formed of a superconductor. The method of claim 1, wherein the upper and lower electrodes A nanoelectronic device using nonlinear conduction properties of a metal spiral thin film, which is formed of a multilayer thin film of a ferromagnetic material or an alloy of a group 3 transition element such as an alloy of a ferromagnetic material and a rare earth transition metal alloy, or a ferromagnetic material and a non-ferromagnetic material. The method of claim 4, wherein the forcing is Co, Fe, Ni, the ferromagnetic alloy of CoFe, NiFe, the non-ferromagnetic material is a non-linear conduction of the metal spiral thin film, characterized in that the precious metals such as Pd, Pt, Ir, Cr, Cu, Au, Ag and alloys thereof Nano electronic device using characteristics. The method of claim 1, wherein the magnetic field is A nanoelectronic device using the nonlinear conduction characteristics of a metallic spiral thin film, which is applied by using a permanent magnet or an electromagnet from the exterior of the metallic thin film having a spiral structure. Electrodes are formed on upper and lower portions of the spiral metal thin film, and an electric field is applied by applying a voltage to the electrodes to apply a magnetic field from the outside so that the metallic thin film of the spiral structure operates as a device having nonlinear conduction characteristics. The resistance value of the metal thin film of the spiral structure is largely changed according to the electric field inside the metal thin film of the spiral structure, the magnetic field applied from the outside and the rotation direction of the spiral structure. Metal diodes using the conduction characteristics. In the nanoelectronic device according to claim 1, according to the direction of the fixed electric field and the direction of the spiral structure, according to the magnetization direction of the magnetic field or the magnetization direction of the magnetic body forming the electrode or the magnetization direction of the magnetic body forming the spiral structure Magnetoresistive element using the nonlinear conduction characteristics of the metal spiral thin film, characterized in that to use the change in the resistance value generated. Inter-electrode is formed between the metal thin films of the spiral structure in different directions, and upper and lower electrodes are formed on the upper and lower portions of the metal thin film of the spiral structure in different directions, and the relative electrode between the inter-electrode, upper and lower electrodes is formed. The nanoelectronic device using the nonlinear conduction characteristics of the metal spiral thin film, characterized in that it is possible to adjust the current value that can flow through the metal thin film of the spiral structure by changing the potential difference between the electrodes.

Images