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WO2001037033A2 - Modulateur spatial de lumière - Google Patents

Modulateur spatial de lumière Download PDF

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Publication number
WO2001037033A2
WO2001037033A2 PCT/US2000/031762 US0031762W WO0137033A2 WO 2001037033 A2 WO2001037033 A2 WO 2001037033A2 US 0031762 W US0031762 W US 0031762W WO 0137033 A2 WO0137033 A2 WO 0137033A2
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WO
WIPO (PCT)
Prior art keywords
electro
modulator
optic material
optic
forming
Prior art date
Application number
PCT/US2000/031762
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English (en)
Other versions
WO2001037033A9 (fr
WO2001037033A3 (fr
Inventor
Feiling Wang
Kewen Kevin Li
Dean Tsang
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Corning Applied Technologies
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Filing date
Publication date
Application filed by Corning Applied Technologies filed Critical Corning Applied Technologies
Priority to AU32629/01A priority Critical patent/AU3262901A/en
Publication of WO2001037033A2 publication Critical patent/WO2001037033A2/fr
Publication of WO2001037033A3 publication Critical patent/WO2001037033A3/fr
Publication of WO2001037033A9 publication Critical patent/WO2001037033A9/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/03—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on ceramics or electro-optical crystals, e.g. exhibiting Pockels effect or Kerr effect
    • G02F1/055—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on ceramics or electro-optical crystals, e.g. exhibiting Pockels effect or Kerr effect the active material being a ceramic
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/03—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on ceramics or electro-optical crystals, e.g. exhibiting Pockels effect or Kerr effect
    • G02F1/0305—Constructional arrangements
    • G02F1/0311—Structural association of optical elements, e.g. lenses, polarizers, phase plates, with the crystal
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/21—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  by interference
    • G02F1/213—Fabry-Perot type
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2202/00—Materials and properties
    • G02F2202/10—Materials and properties semiconductor
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2203/00—Function characteristic
    • G02F2203/12—Function characteristic spatial light modulator
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2203/00—Function characteristic
    • G02F2203/15—Function characteristic involving resonance effects, e.g. resonantly enhanced interaction

Definitions

  • a common example of a simple SLM is a liquid crystal computer display.
  • a two-dimensional array a of liquid crystal cell is uniformly illuminated and the transmission of each cell is controlled to from a display on a screen.
  • each cell corresponds to a pixel in the image.
  • an SLM can perform other functions. For example, a correlation can be obtained between the illuminating image and a second image. This is accomplished by driving the SLM with control voltages that would produce the second image if the illumination were uniform.
  • the SLM output from each cell is the product of the pixel amplitude in the illuminating image and the second image. By collecting and measuring the light from the entire SLM output, the correlation between the two images can be obtained.
  • SLMs have been proposed for use in a variety of diverse applications such as radar signal processing, oil field exploration, weather prediction, air flow simulations, image storage and processing, holographic video systems, large database storage, and optical buses between cache memories in multiprocessors.
  • This invention is in the field of amplitude modulation of light. More particularly, it provides a two-dimensional array of amplitude modulators or a spatial light modulator (SLM) using solid state materials formed using a ceramic-on-silicon fabrication process, for example.
  • SLM spatial light modulator
  • the present invention provides a two dimensional pixellated device that uses a material that has an inherently fast response time as an optical switch.
  • a system is provided for controlling the array that is compatible with existing digital signal processing computers.
  • a silicon CMOS integrated circuit (IC), having random access memories (RAMs), for example, that has been fabricated in a substrate and interfaced to solid state electro-optic materials positioned thereon illustrate a preferred embodiment of the invention.
  • the electro-optic modulators are controlled by RAM cells to produce a modulation in reflected light incident on the device.
  • SRAMs can be used with a connection to the SRAM cell flip-flop.
  • DRAMs can be used with the modulator replacing the DRAM storage capacitor.
  • the SLM thus formed can be connected to a digital computer and controlled as if were a being written to as a memory, but other IC structures can also be used.
  • the electro-optic material is used as the spacer for a Fabry- Perot etalon structure that is also deposited on the RAM substrate.
  • a solid state material such as lead lanthanum zirconate titanate. (PLZT) is a suitable electro-optic material. Proper proportioning of the elements in such a material can be used to avoid thermal mismatch of the material and the substrate.
  • a sequence of layers of the solid state material can be deposited in the liquid phase and heated to provide a sufficiently thick layer without thermal mismatch to the existing substrate.
  • the modulator array is then interconnected to the integrated circuit.
  • FIG. 1 is a cross-sectional view of a single element modulator.
  • FIG. 2 shows light amplitude modulation in response to a 20-volt sinewave.
  • FIG. 3 shows the reflectance of a single element modulator as a function of wavelength when voltages of 0, 10, and 20 volts are applied.
  • FIG. 4 illustrates an array of modulators on a RAM integrated circuit wherein the modulators do not overlap the RAM cells.
  • FIG. 5 is a cross-sectional view of a modulator adjacent a MOSFET driver o an lC.
  • FIG. 6 is a cross-sectional view of a modulator adjacent a MOSFET driver on an IC that uses a copper metallization process.
  • FIG.7 is a schematic view of a spatial light modulator system in accordance with the invention.
  • FIG.8 is a process flow sequence for fabricating a spatial light modulator in accordance with the invention.
  • FIG. 1 illustrates a single cell for an SLM.
  • This cell is located on a silicon CMOS IC RAM in the position normally occupied by the RAM's storage capacitor.
  • the cell structure comprises the RAM's silicon substrate 11, an SiO 2 passivation layer 12, a platinum layer 13, a bottom transparent conductive indium tin oxide (ITO) layer 15, and a dielectric material 25 to form the bottom mirror 14, a solid state electro-optic material 16, a top transparent conducting ITO layer 17, and a top dielectric material 24 that forms the mirror 18.
  • Contact is made to the bottom ITO layer with aluminum metallization 19 and to the top ITO layer with metallization 20 having a sidewall 22 that is insulated from other conductive layers by the SiO 2 deposition 21.
  • the aluminum metallizations connect to address lines that connect to transistor drivers.
  • the top mirror and the bottom mirror form a Fabry-Perot etalon whose overall reflectivity is high except at a resonance wavelength determined by the optical path length in the electro-optic material.
  • the results are the same as for a classical Fabry-Perot etalon with an air space whose path length is varied by moving one of the mirrors.
  • application of a voltage changes the index of refraction and, if it is piezoelectric, its physical thickness. More details can be found in copending application serial no.: 09/420,475, filed October 19, 1999 by Feiling Wang, the entire contents of which is incorporated herein by reference.
  • the top and bottom mirrors are dielectric stacks of alternating layers of low and high index of refraction material having an optical thickness of one quarter the wavelength of the light being reflected.
  • Common materials for this purpose are SiO 2 and TiO 2 or Ta 2 O 5 and deposition of these is compatible with silicon CMOS RAMs.
  • platinum layer 11 a 520 ran thick SiO 2 layer 12, and a 300 nm thick ITO layer, for example, only three periods of alternating layers of SiO 2 and Ta 2 O 5 are needed to achieve a 98% reflectivity for the bottom mirror 14.
  • the top mirror 18 needs six periods, however.
  • the incident light 28 is selectively modulated to control the output optical signal 29.
  • a process for making an SLM on a silicon IC wafer having isolated, but functioning, p-channel MOSFETs and a 1 ⁇ m feature size was undertaken as follows.
  • Lead lanthanum zirconate titanate (PLZT) was chosen as the electro-optic material, but this requires a process temperature in excess of the aluminum metallization's melting point of 660 °C.
  • the aluminum was removed using a 95% phosphoric - 5% nitric acid etch leaving the, as supplied, SiO 2 layer.
  • the electro-optic layer 16 was formed using a dip coating process.
  • the process includes dipping into a solvent-based solution, withdrawing, heating to evaporate the solvent and hardening the solute on the surface. The step can be repeated to build up the thickness.
  • An apparatus for automating the process when used for coating small substrates with oxides such as PLZT is described in "An Automatic Dip Coating Process for Dielectric Thin and Thick Films, K. K. Li et al, Integrated Ferroelectrics, Vol. 3, pp 81-89 (1993), incorporated herein by reference. Coating was undertaken using an apparatus such as that described in the reference.
  • the one constructed included a 45-cm long vertical tube furnace positioned about 12 cm above the dip-coating solution container. This container was at ambient since the solutions are resistant to hydro lyzation.
  • a wafer holder was connected to a chromel wire that passed through the tube furnace and a small hole in a cap at the top and then to a computer controlled pulling motor.
  • a homogeneous solution of precursors for the three cations (Pb "* ⁇ , La + ⁇ + , and Ti ++T+ ) was obtained by mixing appropriate amounts of lead subacetate, hydrated lanthanum acetate, and titanium di-isopropyl bis acetylacetonate in methyl alcohol. The concentration was about 8 grams of PLT per 100 grams of solution.
  • a base coating of PLT can facilitate the nucleation of the PLZT. The substrate was dipped into the solution at the rate of 5 mm/sec and immediately pulled out into the furnace at the same rate.
  • the coating dried. After reaching the center of the furnace, the substrate was held there for 2 minutes (soaked) to fire the coating at a temperature of 700°C. This temperature level is also used for annealing silicon CMOS wafers. Then the substrate was lowered out of the furnace at about 5 mm/sec. into the solution. It also took about 24 sec. to travel from the bottom of the furnace to the solution, during which time the substrate cooled down. Two coats of PLT were applied with an estimated total thickness of 20 nm in this example.
  • a PLZT with a formula of (Pb 1 _ x La x )(Zr y Ti,. y )O 3 precursor solution was prepared.
  • Zirconium acetate was used for the Z ⁇ ++++ cation.
  • the dip coating sequence was the same as for the PLT layers, but 25 coats were applied to achieve a total thickness of PLT and PLZT of about 1290 nm.
  • the 1290 nm thickness stated above produces an optical thickness in the PLZT of 10 integer multiples of half a wavelength for a He-Ne laser. The thickness is an estimate based on the number of coats.
  • the ITO layer was then sputter deposited, followed by the top SiO 2 and Ta 2 0 5 dielectric mirror. Next, using a standard photolithography process with 16% hydrochloric acid, the top mirror was etched, followed by the top ITO and PLZT layers. Aluminum was evaporated to form the contacts.
  • the p-channel MOSFETs are operational and can be used as a control circuit for the display modulator.
  • Single modulator elements were illuminated with a 633 nm He-Ne laser and a 20-volt peak-to-peak sinewave was applied.
  • a typical result for one element is shown in FIG. 2.
  • the lower trace shows the applied voltage and the upper trace indicates the intensity modulation of the reflected light. Note that the lower trace is 90° out of phase and the laser angle of incidence was a few degrees off normal in order to obtain the maximum effect from the etalon. In practice, a tunable laser is desirable.
  • a preferred method of making a single element modulators includes depositing a three period dielectric stack on a silicon wafer followed by a sputter deposited a 300 nm (quarter wavelength) ITO film onto the dielectric stack. On receipt, the wafer was annealed at 550 °C using the annealing cycle for the previous example.
  • PLZT was deposited by dip coating following the procedure above to a thickness of about 1 ⁇ m. ITO was sputter deposited on the PLZT layer. The resulting film did not look transparent, most likely because the sputtering was performed at room temperature without an oxygen atmosphere. A 2 hour 450 °C anneal in air produced a light transparent film with a resistance of about 100 ⁇ /r .
  • a lift off technique with an hydrochloric acid etch was used to remove portions of the ITO layer and produce isolated areas 300 ⁇ m wide by 500 ⁇ m long. Platinum was sputter deposited over patterned photoresist and lifted off to make connections to the ITO areas with platinum and gold used for contact pads.
  • the top dielectric stack was deposited using SiO 2 and Ta ⁇ O j covering the entire wafer.
  • the stack was etched in 1 to 5 diluted hydrofluoric acid to open windows to the contact pads.
  • FIG. 3 shows light reflected from one of the elements as a function of wavelength for applied voltages of 0, 10, and 20 volts. Maximum modulation can be achieved by selecting the wavelength used. As illustrated, a wavelength of about 680 nm produces a 15% change in reflectivity with a 20 volts applied.
  • One problem in depositing PLZT on silicon is the difference in thermal expansion coefficients that causes cracking of the deposited PLZT films due to temperature cycling during deposition.
  • the difference can be reduced by using different formulations for the PLZT.
  • increasing the amount of zirconium and decreasing the amount of lanthanum is one preferred method of improving thermal matching of the electro-optic film to the silicon substrate.
  • the PLZT can be deposited on a silicon IC with suitable circuitry for driving the electro-optic elements.
  • MOSFET ICs There are several possible commercial sources of MOSFET ICs. Hewlett Packard Co., Marina Del Ray, California has a RAM structure that uses a standard 0.8 ⁇ m feature size suitable for 5-volt operation. Meadowlark Optics, Inc., Frederick, Colorado, has a wafer designed for driving liquid crystal SLMs that is suitable for 15-volt operation. The part numbered Z468A01 normally drives a Hex 69 SLM. This uses Mitel Semiconductor's CT43H process. A German manufacturer, ExFab, has an IC process design with a 1 ⁇ m feature size and 100-volt breakdown.
  • FIG. 4 illustrates an array of modulators 31 positioned adjacent corresponding RAM cells 32 on a silicon substrate 11.
  • RAMs dynamic (DRAMs) and static (SRAMs).
  • DRAMs dynamic
  • SRAMs static RAMs
  • the modulator element replaces the storage capacitor used for memory.
  • DRAMS have the advantage of having smaller cell sizes so that the fill factor, the percentage of the chip area covered by modulator are is maximized.
  • SRAM cells have flip-flops that have one output that toggles between a 0 and a 1 state, i.e., 0 volts and the chip supply voltage. In this case, the output is connected to one of the modulator contacts, e.g., 21 in FIG. 1 with the other contact 19 grounded.
  • FIG. 5 illustrates a finished modulator deposited on a RAM (or other) IC and connected to a MOSFET.
  • the modulator is similar to the modulator illustrated in FIG. 1 and like numerals are used to designate like layers.
  • the position of a MOSFET transistor 61 is indicated by the arrow.
  • the process of making, starting with a finished RAM IC using aluminum metallization 62, is as follows. First, the aluminum metallization 62 is removed with 95% phosphoric - 5% nitric acid. Then a layer of ITO 63 is sputter deposited over the entire wafer. This layer is used as an etch stop, not a contact.
  • a sputter deposited layer of SiO 2 (or Si 3 N 4 ) 64 is followed by a sputter deposited layer of SiO 2 (or Si 3 N 4 ) 64. Then a second layer of platinum 13 is deposited to form a base for the dielectric stack 25 that is then deposited. On top of this, a bottom contact ITO layer 15 is deposited, followed by a PLZT layer 16, a top contact ITO layer 17 and the top dielectric stack 24, all as above.
  • the procedure includes selectively patterning with resist and etch selective layers until the underlying gate, source, and drain regions of the IC were again exposed.
  • the top dielectric stack 24 can be etched with hydrofluoric acid (HF). HF, however, does not etch ITO 17. It is etched with hydrochloric acid (HC1) to leave a projection out from under the top dielectric stack. HC1 does not etch the dielectric stack, nor PLZT, or Si0 2 . Then, the PLZT layer 16 is selectively etched with HF. The bottom ITO electrode 15 is etched with HC1 leaving a projection out from under the PLZT. Then, HF is used to etch the dielectric stack 25.
  • HF hydrofluoric acid
  • the platinum layer 13 is removed with a lift-off technique.
  • HF is used for the Si0 2 layer 64, while the etch stop ITO layer 63 prevents the HF from attacking the gate oxide and silicon source and drain regions. This leaves isolated modulator cells sitting on the insulating layer underneath.
  • the ITO 63 is then etched away to expose them.
  • aluminum is evaporated and patterned with the 95% phosphoric - 5% nitric acid. Generally, at least two layers of metallization are required. As illustrated, the top ITO contact layer connects to a source (or drain) of on of the MOSFETs.
  • the bottom contact ITO layer is connected to a ground bus.
  • FIG. 6 illustrates a finished structure that is similar except that an extra oxidation protection layer 73 is used. The process is slightly different as the pixelated structure is formed over layer 73. Rather than removing the copper metallization 72, the first step is to deposit either SiO 2 or Si 3 N 4 to protect it from oxidation. After that, the deposition steps are the same.
  • the process of isolating and making electrical contacts proceeds as for the aluminum metallization wafer including the etching of the ITO etch stop layer. At this point, it is necessary to etch windows 74 in the oxidation protection layer over the copper metallization 72 contacting the source (or drain) of one of the MOSFET driving transistor 71 and a ground bus.
  • the last step is to connect the top ITO layer 17 contact to the MOSFET 71 with metallization 20 that is insulated by an SiO 2 layer 21 that isolates the sidewall from the layers and to connect the bottom ITO layer 15 contact to a ground bus.
  • Design of a PLZT-based SLM that are to be deposited on RAM chips must take into account two material properties, capacitance and modulation sensitivity.
  • the PLZT layers are fairly thick, but with a dielectric constant of about 500, the capacitance is still high.
  • a 20 ⁇ m x 20 ⁇ m element area with a nominal 1 ⁇ m thick layer has a capacitance of about 1.8 pf.
  • the typical MOSFET for a RAM cell has a maximum current source or sink capability of less than about 0.1 ma because this is adequate to charge parasitic or DRAM capacitance.
  • small gate widths can be used and chip size minimized.
  • the gate widths and, hence, drive currents can be increased proportionately.
  • a simple totem pole buffer can be provided.
  • the width of the gates are increased as needed.
  • the input is connected to one of the flip-flop outputs and the output to one contact on the modulator element.
  • Increasing gate width also increases the MOSFET input capacitance. Therefore, it may be desirable to buffer the modulator driving buffer with an input totem pole buffer in order not to load the RAM circuitry and slow it down.
  • the maximum rate of change of driving voltage is 0.55 v/ns. This means that if 15 volts were required for adequate modulation, 24 ns would be required to reach it. The modulation efficiency is not significantly effected if the frame rate were in the millisecond range.
  • the slew rate limits the pixel refresh cycle time to longer than this. This is not a serious limitation. For example, assuming even a 1024 x 768 array, a 60 Hz frame rate and a 16 bit address architecture, the maximum refresh cycle is about be 230 ns. If the element were reduced to 19 ⁇ m square, even a 0.1 ma drive is adequate.
  • the limit on reducing element size is due to optical diffraction effects that become pronounced when the pixel size approaches the wavelength of the incoming light. Even a 20 ⁇ m size produces some diffraction effects and some applications may benefit from larger element sizes such as 50 ⁇ m. This requires a chip size of about 50mm (2 inches) and 8 inch diameter wafers are available for fabrication. Those skilled in the art will appreciate that there are a number of tradeoffs that depend on the particular application. For instance, useful SLMs do not all require such high definition as in the example just given. With the modulation sensitivity of the PLZT modulators, five volts is inadequate for many applications. CMOS transistors have been produced for 15-volt operation.
  • power MOSFETs with a 1 kV breakdown are available.
  • the voltage breakdown is a function of the separation between the source and the drain and the thickness of the gate oxide. Higher voltage operation can be achieved by increasing both.
  • the design and production of a high voltage RAM is, in some respects, easier.
  • the larger chip area and slower speeds can limit the number of pixels. This can be ameliorated because the large PLZT capacitance makes the use of dynamic RAMs possible and attractive.
  • FIG. 7 shows a modulator system in which light 112 from a laser or other light source 110 is directed by optics 108 onto a beamsplitter 103 such that light is directed onto modulator 100.
  • Modulator and the on-board driver, memory and/or control circuits can be controlled by an external digital signal processor such as computer 102.
  • the modulated output signal is reflected by beamsplitter 103 through any required optics 104 onto a detector 106 that can include an optical memory and/or image processing system.
  • FIG. 8 illustrates a process sequence in accordance with the invention as described in greater detail above. First an integrated circuit on a semiconductor substrate is provided 120. Second, an optional protective layer is formed 130 over the circuit.
  • a series of layers of electro-optic material is formed by repeated deposition and temperature cycling 140. This is followed by patterning and interconnecting 150 the pixel array to the circuit.

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Semiconductor Integrated Circuits (AREA)
  • Liquid Crystal (AREA)
  • Mechanical Light Control Or Optical Switches (AREA)

Abstract

L'invention concerne un modulateur constitué d'un matériau électro-optique solide présentant une structure pixélisée interconnectée à un circuit sur un substrat de semi-conducteur. Des circuits intégrés CMOS sur silicium qui peuvent comporter des mémoires vives (RAM) sont utilisés comme substrat et interfacés sur un matériau électro-optique solide appliqué sur ces circuits. D'une manière spécifique, les modulateurs électro-optiques sont commandés par des cellules RAM afin de produire une modulation de lumière réfléchie. La présence d'un dispositif de bascule de cellules SRAM permet d'utiliser des mémoires SRAM. Des mémoires DRAM peuvent être utilisées avec le modulateur remplaçant la capacité de stockage DRAM. Le modulateur spatial de lumière ainsi obtenu peut être connecté sur un ordinateur numérique et commandé comme s'il était inscrit comme une mémoire, mais d'autres structures de circuits intégrés peuvent également être utilisées. Afin d'améliorer les effets de modulation, le matériau électro-optique est utilisé comme partie d'espacement pour une structure d'étalon Fabry-Pérot qui est également déposée sur un substrat de semi-conducteur. Le titanate zirconate de lanthane et de plomb (PLZT) constitue un matériau électro-optique approprié.
PCT/US2000/031762 1999-11-18 2000-11-17 Modulateur spatial de lumière WO2001037033A2 (fr)

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AU32629/01A AU3262901A (en) 1999-11-18 2000-11-17 Spatial light modulator

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US16638099P 1999-11-18 1999-11-18
US60/166,380 1999-11-18

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6746618B2 (en) 2002-05-21 2004-06-08 Corning Incorporated Electro-optic ceramic material and device
US6890874B1 (en) 2002-05-06 2005-05-10 Corning Incorporated Electro-optic ceramic material and device
WO2007034435A3 (fr) * 2005-09-23 2009-03-05 Koninkl Philips Electronics Nv Dispositif compact de stockage de donnees holographiques

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1172852A (en) * 1966-03-11 1969-12-03 Plessey Co Ltd Improvements in or relating to Light Modulation Devices
KR940006708B1 (ko) * 1989-01-26 1994-07-25 세이꼬 엡슨 가부시끼가이샤 반도체 장치의 제조 방법
JPH0418767A (ja) * 1990-05-11 1992-01-22 Nec Corp 空間光変調装置
US5221989A (en) * 1991-11-13 1993-06-22 Northrop Corporation Longitudinal plzt spatial light modulator

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6890874B1 (en) 2002-05-06 2005-05-10 Corning Incorporated Electro-optic ceramic material and device
US6746618B2 (en) 2002-05-21 2004-06-08 Corning Incorporated Electro-optic ceramic material and device
WO2007034435A3 (fr) * 2005-09-23 2009-03-05 Koninkl Philips Electronics Nv Dispositif compact de stockage de donnees holographiques

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WO2001037033A3 (fr) 2002-01-17
AU3262901A (en) 2001-05-30

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