摘要:
A bipolar heterojunction diode has an anode (11, 41), a blocking layer (12, 42) and a junction region (13, 14, 43). a heterojunction (32, 58) in the junction region (13, 14, 43) is utilized to create a misalignment between the band gap of the anode (11, 41) and a band gap of the heterojunction (13, 14, 43). The misalignment prevents a depletion region from extending into the heterojunction (13, 14, 43).
摘要:
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.
摘要:
A method of fabricating 3D semiconductor circuits including providing a conductive layer with doped polysilicon thereon patterned and annealed to form first single grain polysilicon terminals of semiconductor devices. Insulated gate contacts are spaced vertically from the terminals so as to define vertical vias and polysilicon is deposited in the vias to form conduction channels. An upper portion of the polysilicon in the vias is doped to form second terminals for the semiconductor devices, and the polysilicon is annealed to convert it to single grain polysilicon. A second electrically conductive layer is deposited and patterned on the second terminal to define second terminal contacts of the semiconductor devices.
摘要:
Improved methods for selecting memory cells in magnetic random access memory (MRAM) are provided. Whenever a state in a memory cell is sensed, a MRAM requires to adjust an output of comparator to a zero voltage (auto-zeroing step) before the content of memory cell is detected. This invention sequentially accesses memory cells 29-30 once sense line 25 is selected and auto-zeroed. Accordingly, a higher speed operation is attained because the invention does not require an auto-zeroing step every sensing a memory cell.
摘要:
Ultra-small semiconductor devices and a method of fabrication including patterning the planar surface of a substrate to form a pattern edge (e.g. a mesa) and consecutively forming a plurality of layers of semiconductor material in overlying relationship to the pattern edge so that a discontinuity is produced in the layers and a first layer on one side of the pattern edge is aligned with and in electrical contact with a different layer on the other side of the pattern edge.
摘要:
A heterojunction field effect transistor (HFET) having a source, drain, and channel, wherein the channel comprises a quantum well and at least one mono-atomic well or barrier layer is provided. The mono-atomic well or barrier layer has a different bandgap than the channel region and serves to modify electron wave function and conduction band energy in the channel region. Preferably, an indium arsenide well monolayer is formed in an InGaAs channel region and functions to move a first quantized energy level E.sub.0 closer to the bottom of the channel region quantum well thereby increasing electron concentration by increasing effective band offset potential. Another embodiment uses an aluminum arsenide monolayer as a barrier monolayer in the InGaAs channel. By varying location of the monolayers, confinement of electrons in the channel can be improved.
摘要:
A magnetic random access memory (10) has a plurality of stacked memory cells on semiconductor substrate (11), each cell basically having a portion of magnetic material (12), a word line (13), and sense line (14). Upper sense line (22) is electrically coupled to lower sense line (12) via conductor line (23) with ohmic contacts. In order to read and store states in the memory cell, lower and upper word lines (13, 18) are activated, thereby total magnetic field is applied to portion of magnetic material (11). This stacked memory structure allows magnetic random access memory (10) to integrate more memory cells on semiconductor substrate (11).
摘要:
A multi-layer magnetic memory cell including two similar layers of magnetic material stacked in parallel, overlying relationship and separated by a layer of non-magnetic material. Each of the two similar layers have a width that is less than a width of magnetic domain walls within the layer of magnetic material so that magnetic vectors in the two similar layers point along the length thereof. The two similar layers define a central plane parallel with the two similar layers symmetrically formed and positioned thereabout. Magnetic vectors in the two similar layers are switched simultaneously and the two similar layers are positioned close enough together to allow mutual cancellation of pole effects during simultaneous switching of the magnetic vectors.
摘要:
A tunnel transistor including source and drain and a silicon oxide tunneling layer overlying the source. A polysilicon quantum well layer positioned on the tunneling layer and in contact with the drain. The quantum well layer having a thickness which places the ground state above the Fermi level. A silicon oxide insulating layer positioned on the quantum well layer and a gate electrode positioned on the insulating layer overlying the quantum well layer and the source terminal. The tunneling layer being thin enough to allow tunneling between the source and the quantum well layer, and the insulating layer being thick enough to prevent tunneling therethrough.
摘要:
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.