Iwao Takemoto

Ellipsometric study of silicon implanted with boron ions in low doses

Ellipsometry was applied to estimate crystal damage in silicon caused by boron‐ion implantation in low doses. A highly sensitive parameter for crystal damage is proposed which is derived from the extinction coefficient of the complex refractive index. Crystal damage caused by ion implantation at doses as low as 3×1011 cm−2 and the annealing effect on crystal damage of heat treatment in dry N2 ambient after ion implantation were clearly detected by the parameter.

Metal‐oxide‐semiconductor field‐effect transistors fabricated in laterally seeded epitaxial Si layers on SiO2

Metal‐oxide‐semiconductor field‐effect transistors (MOSFET’s) were fabricated in laterally seeded epitaxial Si layers on SiO2, using cw Ar laser irradiation. FET’s were distributed in various regions of the epitaxial films grown on SiO2, as well as directly on a Si substrate. Electronic properties were found to be good when compared with that for bulk Si, even though mobility at the SiO2 edge was somewhat poor. The results are discussed in connection with the crystal qualities examined through use of optical and electron microscopy.

5.4:Silicon Chip Based Reflective PDLC Light Valve for Projection Display

An XGA reflective type light valve is developed using PDLC and a mirror MOS chip fabricated from single crystal silicon. Maximum reflectance of 75% is realized. A projector of 1000ANSI lumen and contrast ratio of 70 is realized with this light valve and a 120W lamp.

2/3-Inch Format MOS Single-Chip Color Imager

A new 2/3-in format MOS single-chip color imager, that includes 384 X 485 elements, has been developed. The device features a low-noise design; high sensitivity (9 nApp/lx for 2855 K W lamp), through employment of a complementary color filter; and wide dynamic range (over 60 dB), through introduction of a p/sup +/-layer in the photodiode and a vertical buffer circuit. The imager also features low aliasing (Moire) and clear color due to the use of a new color filter arrangement and unique multivideo lines. The die measures 10.0 mm X 8.5 mm, which is realized using standard 3-/spl mu/m Si-gate MOSLSI technology. Combining this small size and technological simplicity with on-wafer color filter processing, has made this device suitable for LSI volume production.

A silicon-chip-based light valve with reflective twisted-nematic mode for high-definition projectors

— Crystalline-silicon-chip-based reflective light valves are suitable for realizing high definition and bright liquid-crystal projectors. We have developed an XGA (1025 × 769 pixels) silicon-chip-based light valve with a diagonal display area of 2.54 cm (1 in.). The reflective twisted-nematic mode was examined by using the Jones matrix method as a display mode, and the normally white reflective twisted-nematic mode was selected. This mode is suitable for a narrow cell gap, and a fast response time can be expected. In addition, the driving voltage of this mode is low and has good chromaticity with small retardation. The cell gap of the light valve is 2 μm. The cell gap support is made using spacer posts formed on the silicon chip with a photodefinable resin. The response time is 12 msec, including both rise and fall times. The contrast ratio is more than 1000 at 5 Vrms.

Normally white reflective twisted nematic mode for silicon-chip-based light valves

Crystalline silicon-chip-based reflective light valves are suitable for realizing high definition and bright liquid crystal projectors. We have developed an XGA silicon-chip- based light valve with a diagonal display area of 1 inch. A normally white reflective twisted nematic mode is selected for the valve. An optimum condition of the mode is analytically solved by the Jones matrix method. This mode is suitable for a narrow cell gap and a fast response time can be expected. This mode also has a stable contrast ratio even with temperature and/or cell gap fluctuation. In addition, the driving voltage of this mode is low and it has good chromaticity with small retardation. The cell gap of the light valve is 2 micrometers . The cell gap support is made using spacer posts formed on the silicon chip with a photo- definable resin. The response time is 12 ms including both rise and fall times. The contrast ratio is more than 400 at 5 Vrms.

Solid State Imager Implementing Sensitivity Control Function On Chip

A new solid state imager has been developed, which implements a signal sweep-out circuit for the purpose of controlling sensitivity by the control signal generated in the camera circuitry. Sensitivity can be easily controlled electronically without using a lens iris or a mechanical shutter.

MOS Area Sensor: Part I - Design Consideration and Performance of an n-p-n Structure 484 x 384 Element Color MOS Imager

The design consideration and performance of an n-p-n structure 484 X 384 element MOS imager is described. The imager has a photodiode array and scanners separately integrated on different p wells. The horizontal scanner, consisting of bootstrapping type non-inverting circuits, features high speed and low noise. The maximum scan rate of the scanner is ~15 MHz. The vertical scanner, consisting of inverting circuits, has a wide dynamic operating range. It can operate stably under an intense illumination of ~1500 lx. Analysis of the MOS switch with a photodiode is also carried out. The 484 X 384 imager has shown excellent performances: signal to fixed-pattern-noise ratio of 54 dB, horizontal resolution of 260 TV lines, vertical resolution of 350 TV lines, well-balanced spectral response, and antiblooming.

A wide-band low-noise charge transfer video delay line

A new wide-band low-noise charge transfer video delay line is introduced utilizing a bulk charge transfer device (BCD) with a self-aligned electrode structure, and a simple integrated sample-hold circuit. Brief analysis of charge transfer characteristics of the BCD and design considerations for the proposed device are included. Several kinds of 128-element devices are designed and examined. Measured transferred signal bandwidth is 4 MHz at 10 MHz clock of voltage swing as low as 10 V, with signal-to-noise (S/N) ratio of 42 dB. The device itself can operate beyond 20 MHz clock rate. Moreover, the device features the use of an elaborate sample-hold circuit to eliminate the complex reset pulse and filtering circuitry, high packing density of 18 /spl mu/m per element with 3-/spl mu/m line spacings assuring a high fabrication yield, and process compatibility with conventional Si gate MOS technology.

NCAP projection displays

Projectors based on polymer-eNCAPsulated liquid crystals can provide bright displays suitable for use in conference rooms with normal lighting. Contrast is generated by light scattering among the droplets, rather than by light absorption with crossed polarizers. We have demonstrated a full-color, compact projector showing 1200 ANSI lumens with 200 watts of lamp power - a light efficiency of 6 lumens/watt. This projector is based on low-voltage NCAP material, highly reflective CMOS die, and matched illumination and projection optics. We will review each of these areas and discuss the integrated system performance.