Takashige Tamamushi

Static induction transistor image sensors

New image sensors, based on the operational principle of static induction transistor (SIT), are described in this paper. Two operational modes of SIT image sensors are described here. One is the electron-accumulation mode in which electrons are stored in the floating-cell region and another is the electron-depletion mode in which electrons are removed from the floating-cell region in response to optical input. The electron-depletion mode is superior to the electron-accumulation mode in the charge retention characteristics, its temperature dependence, and the operational tolerancy. The described SIT image sensors, which utilize the vertically configured SITM structure, are very promising for application in very-large-area image converters due to high-speed high-packing density, and wide dynamic range, and especially due to extremely low power dissipation.

Current amplification in nonhomogeneous‐base structure and static induction transistor structure

Current‐amplification mechanisms for a nonhomogeneous‐base bipolar phototransistor (BPT) and a static induction phototransistor (SIPT) are discussed in this paper, and comparisons are made to the homogeneous‐ and or the gradually‐graded‐base BPT. It is shown that the current‐transport mechanism of the BPT with a nonhomogeneously doped ⋅ ⋅ ⋅p+pp+p ⋅ ⋅ ⋅(⋅ ⋅ ⋅ n+nn+n ⋅ ⋅ ⋅) base is similar to that of the SIPT if the p (n) base potential is capacitively controllable both by the p+ (n+) base and collector voltages. For the n‐channel SIPT in the open‐gate mode of operation, the potential‐barrier height for holes stored in the p+‐gate region is higher than the potential‐barrier height for electrons in the source region by the value of VbiGS−VbiG*S, where the VbiGS is the built‐in potential between the p+‐gate region and the n+‐source region of the SIPT and VbiG*S is the potential‐barrier height between the intrinsic gate G* in the channel and the n+‐source region. In fact, a very high dc optical gain G of more ...

Fabrication and optical-switching results on the integrated light-triggered and quenched static induction thyristor

An integrated structure of the light-triggered and light-quenched (LTQ) static induction (SI) thyristor is introduced and is fabricated by the combination of the SI thyristor and SI transistor process technology. The device consists of a buried-gate light triggered (LT) SI thyristor and a p,channel surface gate static induction photo-transistor (SIPT). An anode voltage V<inf>AK</inf>of 500 V at an anode current I<inf>AK</inf>of 1 A (600 A/cm²: channel current density) is optically switched with a triggering power of<tex>P_{LT} = 11</tex>mW/cm²(92 µW) and a quenching power of<tex>P_{LQ} = 11</tex>mW/cm²(110 µW) in a turn-on time of 0.7 µs and a turnoff delay time of 1.0 µs. The integrated LTQ SI thyristor is a novel type of self-turn-off power device that is turned on and off by optical means.

Static Induction Transistor Memory

Vertically configured dynamic SIT memory seems to exhibit high speed and low power operation with high packing density. Basic operations of SIT memory is demonstrated by using a single cell sample and a 36 bit cell array sample particularly on the measurements of the retention characteristic with temperature variations and the speed performance. In SIT memory, the voltage source is not supplied to the storage capacitor, so that there can exist two operational modes, i.e., majority carrier accumulation mode and the depletion mode. The depletion mode is found to be superior to the accumulation mode in the memory retention characteristics. These two modes of SIT memory operations are compared with the conventional dynamic MOS RAM operations.

Totally light controlled static induction thyristor

Abstract A Totally Light Controlled Static Induction Thyristor is described in this paper concentrating on the optical direct/indirect triggering and quenching mechanisms. Up to the present time, using two GaAs infrared LEDs ( λ = 880 nm , T r = 12 ns ), 300V - 1.7A is directly triggered and quenched in a turn-on time of 1.9μs and a turn-off time of 6μs, 540V - 1A is indirectly triggered and directly quenched in a turn-on time of 545ns and a turn-off time of 7.15μs, and 400V - 1A is indirectly switched in a turn-on time of 630ns and a turn-off delay time of 660ns.

Totally Light Controlled Thyristor-Optically Triggerable and Optically Quenchable Static Induction Photo-Thyristor

Optically Triggerable and optically quenchable Static Induction Photo-Thyristor (SIP Thy) is described in this paper concentrating on the optical direct/indirect Triggering and optical quenching mechanisms. Using only two LEDs drived by CMOS logic IC, 300V-2A is directly triggered and quenched in a turn-on time of 6.2psec and a turn-off time of 15psec, and 540V-lA is indirectly switched in a turn-on time of 545nsec and a turn-off time of 7.lSpsec, until now.

Non-destructive image sensor

New imaging device characterized by non-destructive read-out operation is discussed theoretically concentrating on an optical sensing process and a read-out process. The light information is continuously stored in this imaging device even during the read-out process. It has been demonstrated theoretically that the stored voltage is almost independent of the storage capacitance due to the existence of the floating n+p contact and that the read-out voltage is almost independent of the bit line capacitance. The new imaging device has excellent features such as non-destructive characteristic, high sensitivity and wide dynamic range.

A very high sensitivity and very high speed light triggered and light quenched static induction thyristor (LTQSIThy)

The purpose of this paper is to describe a new operational mode of the Static Induction Thyristor (SIThy), namely the Light Triggered and Light Quenched Static Induction Thyristor (LTQSIThy) characterized by the very high triggering and quenching optical sensitivity and very high speed performance. The LTQSIThy is the totally light controlled self-turn-off type power switching device which is constructed by the optically triggerable Static Induction Photo-Thyristor (SIPThy) and the light sensitive element which is connected or integrated to the gate terminal of the SIPThy.