Leland Stanford Junior University

T-ram Semiconductor, Inc.

United States of America As Represented by the Secretary of the Air Force

James D Plummer

Farid Nemati

Kevin J Yang

Scott T Robins

Hyun-Jin Cho

Peter B Griffin

Kailash Gopalakrishnan

Srinivasa Banna

Yue Liang

Donald W Pettibone

Jonathan A Fan

Zachary K Lee

Yaocheng Liu

James D Meindl

Maxwell G Maginness

Kai Zhang

Michael D Deal

Bert A Auld

Robert C Taft

Xue Bai Pitner

Jia Feng

Shu-Lu Chen

A single-crystalline metal is created on a substrate by liquefying a metal material contained within a crucible while in contact with a surface of the substrate, cooling the metal material by causing a temperature gradient effected in the substrate in a direction that is neutral along the surface of the substrate and, therein, growing the single-crystalline metal in the crucible.

Single metal crystals

In a method of fabricating a semiconductor memory device, a thyristor may be formed in a layer of semiconductor material. Carbon may be implanted and annealed in a base-emitter junction region for the thyristor to affect leakage characteristics. The density of the carbon and/or a bombardment energy and/or an anneal therefore may be selected to establish a low-voltage, leakage characteristic for the junction substantially greater than its leakage absent the carbon. In one embodiment, an anneal of the implanted carbon may be performed in common with an activation for other implant regions the semiconductor device.

Thyristor device with carbon lifetime adjustment implant and its method of fabrication

Single-crystalline growth is realized using a liquid-phase crystallization approach involving the inhibition of defects typically associated with liquid-phase crystalline growth of lattice mismatched materials. According to one example embodiment, a semiconductor device structure includes a substantially single-crystal region. A liquid-phase material, such as Ge or a semiconductor compound, is crystallized to form the single-crystal region using an approach involving defect inhibition for the promotion of single-crystalline growth. In some instances, this defect inhibition involves the reduction and/or elimination of defects using a relatively small physical opening via which a crystalline growth front propagates. In other instances, this defect inhibition involves causing a change in crystallization front direction relative to a crystallization seed location. The relatively small physical opening and/or the change in crystalline front direction may be implemented, for example, using a material that is substantially unreactive with the liquid-phase material to contain the crystalline growth.

Crystalline-type device and approach therefor

A thyristor-based memory device may comprise two base regions of opposite type conductivity formed between a cathode-emitter region and an anode-emitter region. A junction defined between the p-base region and the cathode-emitter region of the thyristor may be 'treated' with a high ionization energy acceptor such as indium in combination with carbon as an activation assist species. These two implants may form complexes that may extend across the junction region.

Thyristor-based semiconductor device with indium-carbon implant and method of fabrication

Negative differential resistance devices are implemented to facilitate current flow under different operating conditions. According to an example embodiment of the present invention, an NDR device is arranged for selective passage of current through relatively high tunneling efficiency regions and relatively low tunneling efficiency regions. In some applications, a gate is used to accumulate carriers to facilitate the passage of current that is predominantly one of tunneling current and generation current, respectively, by controlling the passage of current through a relatively high tunneling efficiency region and a relatively low tunneling efficiency region. In some implementations, the NDR device is arranged to mitigate leakage in a storage device using a two-terminal connection.

Negative differential resistance devices and approaches therefor

Single-crystalline growth is realized using a liquid-phase crystallization approach involving the inhibition of defects typically associated with liquid-phase crystalline growth of lattice mismatched materials. According to one example embodiment, a semiconductor device structure includes a substantially single-crystal region. A liquid-phase material is crystallized to form the single-crystal region using an approach involving defect inhibition for the promotion of single-crystalline growth. In some instances, this defect inhibition involves the reduction and/or elimination of defects using a relatively small physical opening via which a crystalline growth front propagates. In other instances, this defect inhibition involves causing a change in crystallization front direction relative to a crystallization seed location. The relatively small physical opening and/or the change in crystalline front direction may be implemented, for example, using a material that is relatively unreactive with the liquid-phase material to contain the crystalline growth.

A thyristor device can be used to implement a variety of semiconductor memory circuits, including high-density memory-cell arrays and single cell circuits. In one example embodiment, the thyristor device includes doped regions of opposite polarity, and a first word line that is used to provide read and write access to the memory cell. A second word line is located adjacent to and separated by an insulative material from one of the doped regions of the thyristor device for write operations to the memory cell, for example, by enhancing the switching of the thyristor device from a high conductance state to a low conductance state and/or from the low conductance state to the high conductance. This type of memory circuit can be implemented to significantly reduce standby power consumption and access time.

Thyristor-type memory device

A thyristor-based semiconductor memory device may comprise at least a region thereof, e.g., a p-base region, having high ionization energy impurity, such as a dopant. This high ionization energy impurity within a base region may be operable to compensate for a gain-versus-temperature dependence of a constituent bipolar transistor of the thyristor element of a thyristor-based memory device. In particular embodiments, the high ionization energy impurity may include a donor and/or acceptor in silicon.

Thyristor-based semiconductor device and method of fabrication

A novel capacitively coupled NDR device can be used to implement a variety of semiconductor circuits, including high-density SRAM cells and power thyristor structures. In one example embodiment, the NDR device is used as a thin vertical PNPN structure with capacitively-coupled gate-assisted turn-off and turn-on mechanisms. An SRAM based on this new device is comparable in cell area, standby current, architecture, speed, and fabrication process to a DRAM of the same capacity. In one embodiment, an NDR-based SRAM cell consists of only two elements, has an 8 F footprint, can operate at high speeds and low voltages, has a good noise-margin, and is compatible in fabrication process with main-stream CMOS. This cell significantly reduces standby power consumption compared to other types of NDR-based SRAMs.

Semiconductor capacitively-coupled NDR device and related applications in high-density high-speed memories and in power switches

Manufacture of semiconductor capacitively-coupled NDR device for applications such as high-density high-speed memories and power switches

A novel capacitively coupled NDR device can be used to implement a variety of semiconductor circuits, including high-density SRAM cells and power thyristor structures. In one example embodiment, the NDR device is used as a thin vertical PNPN structure with capacitively-coupled gate-assisted turn-off and turn-on mechanisms. An SRAM based on this new device is comparable in cell area, standby current, architecture, speed, and fabrication process to a DRAM of the same capacity. In one embodiment, an NDR-based SRAM cell consists of only two elements, has an 8F footprint, can operate at high speeds and low voltages, has a good noise-margin, and is compatible in fabrication process with main-stream CMOS. This cell significantly reduces standby power consumption compared to other type of NDR-based SRAMs.

Semiconductor current-switching device having operational enhancer and method therefor

A novel capacitively coupled NDR device can be used to implement a variety of semiconductor circuits, including high-density SRAM cells and power thyristor structures. In one example embodiment, the NDR device is used as a thin vertical PNPN structure with capacitively-coupled gate-assisted turn-off and turn-on mechanisms. An SRAM based on this new device is comparable in cell area, standby current, architecture, speed, and fabrication process to a DRAM of the same capacity. In one embodiment, an NDR-based SRAM cell consists of only two elements, has an 8 F,footprint, can operate at high speeds and low voltages, has a good noise-margin, and is compatible in fabrication process with main-stream CMOS. This cell significantly reduces standby power consumption compared to other types of NDR-based SRAMs.

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Portola Valley, CA, United States of America

James D Plummer