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 method of fabricating semiconductor devices including defining an area on the surface of a substrate, selectively growing, on the area, a crystalline material with at least one defined crystallographic facet, and selectively growing a semiconductor device on the crystallographic facet. In a second embodiment, an area is defined on the surface of a substrate and chemical beam epitaxy is used to selectively grow, on the area, a layer of indium arsenide with at least one defined crystallographic facet.
摘要:
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.D) and to provide holes to the first undoped channel (11,14) when the second material composition has a valence band maximum greater than the doping energy level (E.sub.D).
摘要:
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).
摘要:
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).
摘要:
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.
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).