Abstract: An improved and novel fabrication method for magnetoresistive random access memory (MRAM) is provided. An MRAM device has memory elements and circuitry for managing the memory elements. The circuitry includes transistor (12a), digit line (29), etc., which are integrated on a substrate (11). The circuitry is fabricated first under the CMOS process and then magnetic memory elements (53, 54). A dielectric layer (40, 41) is deposited on the circuit, and trenches (42, 43) are formed in the dielectric layer. A blanket layer (46), which includes magnetic layers (48, 49) and a non-magnetic layer (50) sandwiched by the magnetic layers, is deposited on dielectric layer (41) and in the trenches. Then, the blanket layer outside the trenches is removed and MRAM elements (53, 54) are formed in the trenches.

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 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 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 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 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: 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: An enhanced mobility semiconductor comprising a host quantum well having at least two charge carrier barrier layers of a wide bandgap material, each of the two charge carrier barrier layers being separated by a conducting region containing charge carriers is provided. A number of phonon barriers having a predetermined thickness are formed in the conducting region wherein the predetermined thickness is chosen to allow charge carrier tunneling through the phonon barriers.

Abstract: A heterojunction field effect transistor structure having a plurality of vertically stacked field effect devices. Two or more devices having electrically independent source and drain regions are formed such that a single gate electrode controls current flow in each of the devices. Each of the vertically stacked FETs have electrically isolated channel regions which may be controlled by a single gate electrode. Vertically stacked devices provide greater device packing density.

Abstract: An enhanced conductivity structure comprising first and second coupled quantum well channel layers spaced from each other by a barrier layer of predetermined thickness is provided. The barrier layer and other supporting layers comprise a first material type, while the first and second quantum wells comprise a second material type having a narrower bandgap than the first material type. Each of the quantum wells is thin to confine current flow to the plane of the quantum wells. First and second spacer layers of the first material type are formed adjacent to each of the quantum wells, and planar doping layers are provided on each of the spacer layers. First and second buffer layers of the first material type are formed adjacent to each of the spacer layers.

Abstract: A heterojunction field effect transistor (HFET) having a source, drain, and channel, wherein the channel is a top layer of a superlattice buffer, eliminating the need for a thick buffer layer. The superlattice buffer comprises alternating barrier and quantum well layers which are thin enough to provide wide separation in energy bands within the quantum wells. In a preferred embodiment the channel comprises a quantum well and one to five monolayers having a different bandgap than the channel region and serves to modify electron wave function and conduction band energy in the channel region. Preferably, a ten period AlAs/GaAs superlattice is formed underneath the channel.