PLZT reflective displays

Haertling, Gene H.

doi:10.1080/00150198308014433

Cited by 11 publications

(3 citation statements)

References 10 publications

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“…In recognition of this problem of properly evaluating new processes, a study was made of several new chemical co-precipitation methods for the preparation of PLZT powders which involved comparing them directly with the mixed oxide and alkoxide processes. 8 The methods selected were (1) acetate, (2) oxalate, (3) ammonia, (4) ammonium carbonate, (5) acetate without precipitation and (6) ammonia without precipitation.…”

Section: Processesmentioning

confidence: 99%

Recent developments in bulk and thin film PLZT materials and devices

Haertling

1992

Ferroelectrics

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Current trends in the electronics and optoelectronics industries involving computing, data processing, sensing and communications all point toward a continuing need for improved materials and new multifunctional structures. The continuing and unrelenting drive toward higher bit density and greater integration has led many of the new technologies away from bulk materials and to their thin film counterparts. Recent research on thin and thidthick PLZT for ferroelectric and electrooptic applications has also participated in this trend toward thinner structures. Their desirable ferroelectric switching properties have been explored for random access memory applications, whereas, their electrooptic properties have been evaluated for transverse-mode light shutters and modulators. Shutter contrast ratios as high as 500:l have been obtained.

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Section: Processesmentioning

confidence: 99%

Recent developments in bulk and thin film PLZT materials and devices

Haertling

1992

Ferroelectrics

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“…PLZT ceramic material has been used in optical shutter applications for several years. Recently, it has been applied to display devices (2). However, for use as a substrate in dot-matrix applications, several constraints are placed on the process for fabrication of the thin film transistors.…”

mentioning

confidence: 99%

“…The purpose of RTA is to reduce the thermal budget and thereby to prevent significant diffusion of dopants. Recent work (2) has been reported on the use of tungsten-halogen lamps to grow thin device quality silicon dioxide for potential use in MOS VLSI gates. That work was limited to the growth of approximately 130A of SiO2 in dry oxygen at 1150~ The present work extends the temperature range and investigates the growth of thicker oxide for both dry and wet oxidants as well as for (111) and (100) substrates with both boron and phosphorus as dopants.…”

mentioning

confidence: 99%

Fabrication of High Voltage Polysilicon TFT's on an Insulator

Pennell

Catero

Lovelis

1986

J. Electrochem. Soc.

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Using thin film transistors in active-matrixed addressed large area displays has recently become important in display development. Specifically, a PLZT ceramic dot-matrix display requires high voltage TFT pixel switching. To meet the need, a process has been developed utilizing polysilicon and temperatures less than 850~ which yields MOSFET's capable of operating at voltages in excess of 50V with high ID(o,,/IDr ratios. High mobilities are obtained by fabricating n-channel, accumulation-mode devices in silicon deposited in the amorphous state and later annealed to the final polycrystalline condition.Interest has been growing in the use of thin film transistors for addressing active dot-matrix displays. Although several materials have been investigated, polysilicon offers such advantages as the use of conventional silicon processing techniques and an easy fabrication process (1). High quality devices could also be used as driver circuitry fabricated on the display substrate.PLZT ceramic material has been used in optical shutter applications for several years. Recently, it has been applied to display devices (2). However, for use as a substrate in dot-matrix applications, several constraints are placed on the process for fabrication of the thin film transistors. Most of the wet cleaning schemes presently used in MOS processing severely degrade the PLZT surface, reducing its electro-optic effect. Also, thermal stress due to temperature gradients produces breakage at temperatures as low as 150~ High temperatures (over 200~ can alter the PLZT composition with time, changing its electro-optic effect especially, whenever hydrogen is available in the processing atmosphere or in a deposited film. The lead component is easily reduced by hydrogen, rendering the substrate useless. In addition to these material effects are the requirements that the thin film transistors have low leakage currents in the off state with a high source-to-drain voltage and be able to provide sufficient charging current to charge the capacitive load of the pixel during the short time allotted. Also note that the device must be symmetric.Adhering to the constraints of the PLZT substrate, a process has been developed, utilizing deposited oxide encapsulation, suitable for the production of acceptable thin film transistors, which can be used for pixel switching and driver circuitry. A fully populated PLZT dot-matrix display has been fabricated (3). With slight modifications, the process could be valuable in the formation of stacked transistors utilized in MOS DRAM fabrication. TFT ProcessThe fabrication process for buildin~ n-channel MOSFET's in polysilicon is as follows. 2500A of low temperature oxide (LTO) is deposited by LPCVD (on PLZT) at the temperature of 420~ This is followed by the deposition of silicon using LPCVD at 580~ to a thickness of 5000A. Next, the polysilicon islands for TFT fabrication are defined using normal photolithography techniques, and this step is immediately followed by defining regions for source-drain implant utilizing pho...

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Transparent Ferroelectric Ceramics II. Specific Properties and Applications

Krumins¹,

Sternberg²

1987

Springer Proceedings in Physics

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PLZT reflective displays

Cited by 11 publications

References 10 publications

Recent developments in bulk and thin film PLZT materials and devices

Recent developments in bulk and thin film PLZT materials and devices

Fabrication of High Voltage Polysilicon TFT's on an Insulator

Transparent Ferroelectric Ceramics II. Specific Properties and Applications

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