Abstract: A heterostructure electron emitter including a substrate having a surface with a predetermined potential barrier and a quantum well formed in the substrate adjacent the surface. Contacts are positioned on the substrate for coupling free electrons to the substrate and into the quantum well. An acoustic wave device is positioned on the substrate so as to direct acoustic waves to strike the free electrons in the quantum well and excite the free electrons sufficiently to cause the free electrons to overcome the potential barrier and to be emitted from the surface of the substrate.

Abstract: A heterojunction device including a first semiconductive layer on a substrate, a barrier layer on the first layer, a second semiconductive layer on the barrier layer and a multi-layer cap, on the second semiconductive layer. First and second gates positioned on layers of the cap to define first and second transistors, with the cap layers being selected and etched to pin the Fermi level in a first transistor conduction channel in the second semiconductive layer such that the number of carriers in the first conduction channel are substantially less than the number of carriers in surrounding portions of the second semiconductive layer and the Fermi level in a second transistor conduction channel in the first semiconductive layer such that the number of carriers in the second conduction channel are substantially less than the number of carriers in surrounding portions of the first semiconductive layer.

Abstract: A quantum multifunction transistor including a plurality of conduction layers of semiconductor material with a tunnel barrier layer sandwiched therebetween. The conduction layers each being very thin to form discrete energy levels, and the material being chosen so that discrete energy levels therein are not aligned across the tunnel barrier layer in an equilibrium state. A gate coupled to a portion of one of the conduction layers for aligning, in response to a voltage applied thereto, discrete energy levels in the conduction layers across the tunnel barrier layer, whereby majority carrier current flows through the transistor. Application of a higher voltage to the gate results in minority carrier current flow through the transistor.

Abstract: A field effect semiconductor device having multiple vertically stacked channels (12, 14, 16) separated by barrier layers comprising wide bandgap material (18) is provided. The channels (12, 14, 16) are formed on a wide bandgap buffer layer (11) and each channel is coupled a N-type drain region (22b). Each channel is also coupled to an N-type source region (25b). With appropriate gate bias on a gate electrode (17), quantized energy levels in the channels (12, 14, 16) are aligned to provide self-doping by electrons in the valence band of the P-channel (14) moving to the conduction band of the N-channels (12, 16) providing peak channel conductivity. At higher gate bias, one of the N-channels (12) becomes non-conductive creating a negative resistance region.

Abstract: A field effect semiconductor device having multiple vertically stacked channels (12, 14, 16) separated by barrier layers comprising wide bandgap material (18) is provided. The channels (12, 14, 16) are formed on a wide bandgap buffer layer (11) and each channel is coupled a P-type drain region (22b). Each channel is also coupled to an N-type source region (25b). With appropriate gate bias on a gate electrode (17), quantized energy levels in the channels (12, 14, 16) are aligned providing peak current flow by electrons tunneling from the conduction band of one or more N-channels (12, 16) to the valence band of the P-channel (14).

Abstract: A complementary field effect structure having a first field effect device (26) including a quantum well having a first channel (12). A first doping region (14) is positioned adjacent to a first quantum well and a first gate electrode (29) is positioned so that the first doping region (14) is between the first gate electrode (29) and the first channel (12) . A second field effect device (37) includes a second channel (22) and a second doping region (19) positioned adjacent to the second channel. A second gate electrode (31) is positioned over the second channel (22) so that the second channel (22) is between the second gate electrode (31) and the second doping region (19). An interconnect electrically couples the first gate electrode (29) to the second gate electrode (31).

Abstract: A heterojunction device including a first semiconductive layer on a substrate, a barrier layer on the first layer, a second semiconductive layer on the barrier layer and a multi-layer cap, on the second semiconductive layer. First and second gates positioned on layers of the cap to define first and second transistors, with the cap layers being selected and etched to pin the Fermi level in a first transistor conduction channel in the second semiconductive layer such that the number of carriers in the first conduction channel are substantially less than the number of carriers in surrounding portions of the second semiconductive layer and the Fermi level in a second transistor conduction channel in the first semiconductive layer such that the number of carriers in the second conduction channel are substantially less than the number of carriers in surrounding portions of the first semiconductive layer.

Abstract: A semiconductor structure that provides both N-type and P-type doping from a single dopant source is provided. A first doping region (13) comprising a first material composition includes holes and electrons in a doping energy level (E.sub.D)- A first undoped spacer region (12) comprising the first material composition covers the doping region (13). An undoped channel (11,14) comprising a second material composition covers the first spacer region (12) and a second undoped spacer region (12) comprising the first material composition covers the undoped channel (11,14). The first material composition has a wider bandgap than the second material composition and the doping energy level (E.sub.D) is selected to provide electrons to the undoped channel (11,14) when the second material composition has a conduction band minimum less than the doping energy level (E.sub.

Abstract: A low power heterojunction field effect transistor (10, 30, 50, 60) capable of operating at low drain currents while having a low intermodulation distortion. A channel restriction region (9, 38, 51) is formed between the gate electrodes (24, 41, 69) and the drain electrodes (25, 46, 65). The channel restriction region (9, 38, 51) depletes the channel layer (13, 33) thereby constricting a channel and lowering a drain saturation current. The channel restriction region (9, 38, 51) may be used to set a desired drain saturation current such that a second derivative of the transconductance with respect to the gate-source voltage is approximately zero and a first derivative of the transconductance with respect to the gate-source voltage is, approximately, a relative maximum at the desired operating point.

Abstract: A semiconductor structure that provides intrinsic doping from native defects is provided. A quantum well including a narrow bandgap material (11, 14) having a low concentration of native defects is sandwiched between two wide bandgap spacer layers (12, 20, 17, 15). The spacer layers (12, 20, 17, 15) have a low concentration of native defects. At least one doping region (13, 16) having a high concentration of native defects positioned adjacent to one of the undoped spacer layers (12, 17).

Abstract: A high transconductance HFET (21) utilizes nonalloy semiconductor materials (26) to form a strained channel layer (26) that has a deep quantum well (38). The materials utilized for layers adjacent to the channel layer (26) apply strain to the channel layer (26) and create an excess of high mobility carriers in the channel layer (26). The materials also form a deep quantum well (38) that confines the high mobility carriers to the channel (26). The high mobility carriers and the high confinement provide an HFET (21) that has high transconductance, high frequency response, and sharp pinch-off characteristics.

Abstract: A resonant tunneling diode having a quantum well sandwiched between first and second tunnel barrier layers and the quantum well and tunnel barrier layers sandwiched between an injection layer and a collector layer. The improvement includes a relatively thin layer of semiconductor material sandwiched between either the first tunnel barrier layer and the injection layer or the first tunnel barrier layer and the quantum well. The thin semiconductor layer has a valence band with an energy level lower than the valence band of the first tunnel barrier layer so as to prevent minority carriers from travelling toward the injection layer.

Abstract: A quantum well structure having a host optical phonon confinement well (11) having a characteristic phonon distribution (16), and at least one charge carrier confinement well (17) located near a minima of the phonon distribution (16). In one embodiment, a wide bandgap layer (13) is formed in a central portion of the host optical phonon confinement well (11), wherein the wide bandgap layer (13) has phonon properties closely matching that of the host phonon confinement well (11).

Abstract: A semiconductor device having a vertical interconnect or via stacked formed by quantum well comprising a semiconductor material is provided. A first semiconductor device (11) having a current carrying region (19) is formed in a first horizontal plane. A second semiconductor device (12) having a current carrying region (29) is formed in a second horizontal plane. Each of the current carrying regions have a first quantized energy level that is substantially equal. A semiconductor via (31) couples the current carrying region (19) of the first semiconductor device (11) to the current carrying region (29) of the second device (12), wherein the semiconductor via (31) has a first quantized energy level capable of alignment with the quantized energy levels of the current carrying regions (19, 29) of the first and second semiconductor devices (11,12).

Abstract: A thin transition layer (13) is employed to provide alignment between an electron wave function (29) and a hole wave function (37) of an optical modulator (10) for a wide range of applied voltage values that are less than a predetermined value. Over this range of voltages, the modulator (10) is in an off state and substantially absorbs incident light (19). For applied voltages in excess of the predetermined value, the electron (29) and hole wave (37) function alignment is diminished thereby allowing light (19) to be transmitted through the modulator (10).

Abstract: A semiconductor device having a lateral interconnect or via formed by quantum well comprising a semiconductor material is provided. The lateral interconnect (17, 18, 19) formed by a quantum well comprising a first semiconductor material composition. A first semiconductor region (11, 12, 13) comprising a second material type is formed adjacent to the lateral interconnect (17, 18, 19). A second semiconductor region (23, 24, 26) comprising the second material type is adjacent to the lateral interconnect (17, 18, 19) so that the lateral interconnect (17, 18, 19) separates the first (11, 12, 13) and second (23, 24, 26) semiconductor regions. The first (17, 18, 19) and second (23, 24, 26) semiconductor regions have a first quantized energy level that is substantially equal. The lateral interconnect (17, 18, 19) has a first quantized energy level capable of alignment with the quantized energy levels of the first (11, 12, 13) and second (23, 24, 26) semiconductor regions.

Abstract: A resonant tunneling semiconductor device having two large bandgap barrier layers (12, 14) separated by a quantum well (13) is provided. The two barriers (12,14) and the quantum well (13) are formed between first and second semiconductor layers (11, 16) of a first conductivity type. A monolayer (17) of material having a different bandgap than the quantum well material is provided in the quantum well thereby lowering the ground state energy level of the quantum well. Alternatively, monolayers (18, 19) having a different bandgap than that of the first and second semiconductor layers (11, 16) are formed in the first and second semiconductor layers, respectively, outside of the quantum well (13).

Abstract: Logic circuits using a heterojunction field effect transistor structure having vertically stacked complementary devices is provided. A P-channel quantum well and an N-channel quantum well are formed near each other under a single gate electrode and separated from each other by a thin layer of barrier material. P-source and P-drain regions couple to the P-channel. N-source and N-drain regions couple to the N-channel. The P-source/drain regions are electrically isolated from the N-source/drain regions so the P-channel and N-channel devices may be interconnected to provide many logic functions.

Abstract: A field effect semiconductor device having multiple vertically stacked channels (12, 14, 16) separated by independent gate electrodes (13, 15) is provided. The channels (12, 14, 16) are formed on a wide bandgap buffer layer (11) and each channel is coupled a drain electrode (21). Each channel is also coupled to a source electrode (25-26). The quantum well channels (12, 14, 16) and quantum well gates (13, 15) are separated from each other by barrier layers (18) of a wide bandgap semiconductor material.

Abstract: A thin layer, typically a monolayer, of a small band gap material (37) is inserted into the active layer (14) of a quantum well semiconductor device (36, 51). The band gap of the thin layer (37) is smaller than the band gap of the material in the active layer (14), thereby shifting carrier concentrations in the quantum well (26d, 26e, 26h, 26n) of the active layer (14) toward the thin layer (37). This shift increases alignment between the electron wave function (42, 54) and the hole wave function (44, 57) in the quantum well (26d, 26e, 26h, 26n) which increases the probability of stimulated photon emissions thereby reducing the threshold current and threshold voltage of the quantum well semiconductor device (36, 51).