Abstract: According to the present invention, a control gate is formed on an n-type Si substrate, and a p-type source-drain region is formed in the surface of the substrate on both the sides of the control gate. A p-type Si.sub.x Ge.sub.1-x (0.ltoreq.x<1) layer and an Al electrode are sequentially formed in the source-drain region. The energy difference between the valence band of the SiGe layer and a vacuum level is smaller than the energy difference between the valence band of an Si layer constituting the source-drain region and the vacuum level, and the energy difference of the conduction band of the SiGe layer and the vacuum level is larger than the energy difference of the conduction band of the Si layer and the vacuum level. For this reason, a Schottky barrier height is decreased, and resistances between the semiconductor layers and the Al electrode are reduced.

Abstract: A high-speed semiconductor device comprising emitter potential barrier layer disposed between an emitter layer and a base layer, a collector layer, and a collector potential barrier layer disposed between the base layer and the collector layer. The collector potential barrier layer has a structure having a barrier height changing from a high level to a low level along the direction from the base layer to the collector layer, whereby, even when no bias voltage is applied between the collector layer and the emitter layer, a collector current can flow through the device.

Abstract: There is disclosed a field effect transistor comprising a channel layer formed of GaInAs and provided with a planar dope layer doped with an impurity in the form of a two-dimensional thin plane a cap layer and a buffer layer formed respectively in contact with the upper and lower faces of the channel layer, the cap layer and buffer layer being formed of GaInAs whose In composition ratio is lower than that of the channel layer first and a second semiconductor layers formed respectively in contact with the cap layer and the buffer layer, first and second semiconductor layers being formed of GaInAs whose In composition ratio is lower than GaAs or the cap layer and the buffer layer.

Abstract: A method for fabricating a plurality of semiconductor photodetectors and an array of same produced by the method. The method includes a first step of selectively removing semiconductor material to form a channel within a semiconductor material for physically isolating a first photodetector from a second photodetector, the semiconductor material having a characteristic energy bandgap. The method includes a second step of selectively increasing the carrier concentration of the semiconductor material within a bottom region of the channel for preventing minority charge carriers from diffusing under the channel from a region associated with the first photodetector to a region associated with the second photodetector. The step of selectively removing is accomplished by the steps of providing a patterned mask upon the semiconductor material and selectively removing the underlying semiconductor material through an opening within the mask.

Abstract: A three-terminal hot-electron device, in particular a two dimensional electron gas base transistor which can be fabricated by molecular beam epitaxy (MBE). The two-dimensional electron gas is induced in an undoped GaAs quantum well by a modulation doping is used as the base of the transistor and permits a common-base current gain .alpha. to be achieved as high as 0.96 under a collector bias of 2.5 V and an emitter current of 3 mA.

Abstract: Optically pumped coupled quantum well devices are disclosed. The devices store bits as carrier packets in depressions in the conduction and/or valence band(s) of a single crystal; the band between the depressions is sloped in a common direction which provides unidirectionality. The carrier packets are shifted from depression to depression by optically exciting the carriers and relying on the arrangement of depressions and band slopes; the excitation is conveniently performed by laser illumination. The depressions may be sufficiently small to discretize the energy levels and thereby permit the partitioning of the depressions into groups with each group having depressions of substantially the same energy level structure. The carriers in depressions of one group can then be selectively excited by illumination with a laser or narrow band monochromatic incoherent light source tuned to the energy level structure; this allows multiphase operation of the shifting function.

Abstract: A lateral injection group III-V heterostructure device having self-aligned graded contact diffusion regions of opposite conductivity types and a method of fabricating such devices are disclosed. The device includes a heterojunction formed by a higher bandgap III-V compound semiconductor formed over a lower bandgap III-V compound semiconductor. The method of the present invention allows the opposite conductivity type diffusion regions to diffuse simultaneously and penetrate the heterojunction. This results in compositional mixing of the compound semiconductor materials forming the heterojunction in the diffusion regions.