Abstract: A thyristor based semiconductor device includes a thyristor having cathode, P-base, N-base and anode regions disposed in electrical series relationship. The N-base region for the thyristor has a cross-section that defines an inverted “T” shape, wherein a buried well in semiconductor material forms is operable as a part of the N-base. The stem to the inverted “T” shape extends from the upper surface of the semiconductor material to the buried well. The P-base region for the thyristor extends laterally outward from a side of the stem that is opposite the anode region of the thyristor, and is further bounded between the buried well and a surface of the semiconductor material. A thinned portion for the N-base is defined between the cathode region of the thyristor and the buried well, and may include supplemental dopant of concentration greater than that for some other portion of the N-base.

Abstract: A new memory cell can contain only a single thyristor. There is no need to include an access transistor in the cell. In one embodiment, the thyristor is a thin capacitively coupled thyristor. The new memory cell can be connected to word, bit, and control lines in several ways to form different memory arrays. Timing and voltage levels of word, bit and control lines are disclosed.

Abstract: A dynamically-operating restoration circuit is used to apply a voltage or current restore pulse signal to thyristor-based memory cells and therein restore data in the cell using the internal positive feedback loop of the thyristor. In one example implementation, the internal positive feedback loop in the thyristor is used to restore the conducting state of a device after the thyristor current drops below the holding current. A pulse and/or periodic waveform are defined and applied to ensure that the thyristor is not released from its conducting state. The time average of the periodic restore current in the thyristor may be lower than the holding current threshold. While not necessarily limited to memory cells that are thyristor-based, various embodiments of the invention have been found to be the particularly useful for high-speed, low-power memory cells in which a thin capacitively-coupled thyristor is used to provide a bi-stable storage element.

Abstract: A thyristor-based memory may comprise a thyristor accessible via an access transistor. A temperature dependent bias may be applied to at least one of a supporting substrate and an electrode capacitively-coupled to a base region of the thyristor. The voltage level of the adaptive bias may change with respect to temperature and may influence and/or compensate an inherent bipolar gain of the thyristor in accordance with the change in bias and may enhance its performance and/or reliability over a range of operating temperature. In a particular embodiment, the thyristor may be formed in a layer of silicon of an SOI substrate and the adaptive bias coupled to a supporting substrate of the SOI structure.

Abstract: A new memory cell contains only a single thyristor without the need to include an access transistor. A memory array containing these memory cells can be fabricated on bulk silicon wafer. Each memory cell is separated from other memory cells by shallow trench isolation regions. The memory cell comprises a thyristor body and a gate. The thyristor body has two end region and two base regions. The gate is positioned over and insulated from at least a portion of one base region and offset from another base region. A first end region is connected to one of a word line, a bit line and a third line. A second end region is connected to another of the word line, bit line, and third line. The gate is connected to the remaining of the word line, bit line and third line.

Abstract: A new memory cell contains only a single thyristor without the need to include an access transistor. A memory array containing these memory cells can be fabricated on bulk silicon wafer. The memory cell contains a thyristor body and a gate. The thyristor body has two end region and two base regions, and it is disposed on top of a well. The memory cell is positioned between two isolation regions, and the isolation regions are extended below the well. A first end region is connected to one of a word line, a bit line and a third line. A second end region is connected to another of the word line, bit line, and third line. The gate is connected to the remaining of the word line, bit line and third line.

Abstract: 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.

Abstract: A semiconductor device may comprise a partially-depleted SOI MOSFET having a floating body region disposed between a source and drain. The floating body region may be driven to receive injected carriers for adjusting its potential during operation of the MOSFET. In a particular case, the MOSFET may comprise another region of semiconductor material in contiguous relationship with a drain/source region of the MOSFET and on a side thereof opposite to the body region. This additional region may be formed with a conductivity of type opposite the drain/source, and may establish an effective bipolar device per the body, the drain/source and the additional region. The geometries and doping thereof may be designed to establish a transport gain of magnitude sufficient to assist the injection of carriers into the floating body region, yet small enough to guard against inter-latching with the MOSFET.

Abstract: A dynamically-operating restoration circuit is used to apply a voltage or current restore pulse signal to thyristor-based memory cells and therein restore data in the cell using the internal positive feedback loop of the thyristor. In one example implementation, the internal positive feedback loop in the thyristor is used to restore the conducting state of a device after the thyristor current drops below the holding current. A pulse and/or periodic waveform are defined and applied to ensure that the thyristor is not released from its conducting state. The time average of the periodic restore current in the thyristor may be lower than the holding current threshold. While not necessarily limited to memory cells that are thyristor-based, various embodiments of the invention have been found to be the particularly useful for high-speed, low-power memory cells in which a thin capacitively-coupled thyristor is used to provide a bi-stable storage element.

Abstract: A content-addressable memory (“CAM”) architecture and method for reducing power consumption thereof are described. A CAM cell array includes CAM cells, each of which includes two thyristor-based storage elements. Each thyristor-based storage element of the CAM cells has a control gate, an anode, and a cathode for providing control gates, anodes, and cathodes of the CAM cells. The CAM cell array further includes matchlines directly coupled to the cathodes of the CAM cells; searchlines directly coupled to the anodes of the CAM cell; and gatelines coupled to the control gates of the CAM cells.

Abstract: 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.

Abstract: A semiconductor device may comprise a partially-depleted SOI MOSFET having a floating body region disposed between a source and drain. The floating body region may be driven to receive injected carriers for adjusting its potential during operation of the MOSFET. In a particular case, the MOSFET may comprise another region of semiconductor material in contiguous relationship with a drain/source region of the MOSFET and on a side thereof opposite to the body region. This additional region may be formed with a conductivity of type opposite the drain/source, and may establish an effective bipolar device per the body, the drain/source and the additional region. The geometries and doping thereof may be designed to establish a transport gain of magnitude sufficient to assist the injection of carriers into the floating body region, yet small enough to guard against inter-latching with the MOSFET.

Abstract: A method of fabricating a thyristor-based memory may include forming different opposite conductivity-type regions in silicon for defining a thyristor and an access device in series relationship. An activation anneal may activate dopants previously implanted for the different regions. A damaging implant of germanium or xenon or argon may be directed into select regions of the silicon including at least one p-n junction region for the access device and the thyristor. A re-crystallization anneal may then be performed to re-crystallize at least some of the damaged lattice structure resulting from the damaging implant. The re-crystallization anneal may use a temperature less than that of the previous activation anneal.

Abstract: 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.

Abstract: A thyristor-based memory may comprise a thyristor accessible via an access transistor. A temperature dependent bias may be applied to at least one of a supporting substrate and an electrode capacitively-coupled to a base region of the thyristor. The voltage level of the adaptive bias may change with respect to temperature and may influence and/or compensate an inherent bipolar gain of the thyristor in accordance with the change in bias and may enhance its performance and/or reliability over a range of operating temperature. In a particular embodiment, the thyristor may be formed in a layer of silicon of an SOI substrate and the adaptive bias coupled to a supporting substrate of the SOI structure.

Abstract: A semiconductor device may comprise a partially-depleted SOI MOSFET having a floating body region disposed between a source and drain. The floating body region may be driven to receive injected carriers for adjusting its potential during operation of the MOSFET. In a particular case, the MOSFET may comprise another region of semiconductor material in contiguous relationship with a drain/source region of the MOSFET and on a side thereof opposite to the body region. This additional region may be formed with a conductivity of type opposite the drain/source, and may establish an effective bipolar device per the body, the drain/source and the additional region. The geometries and doping thereof may be designed to establish a transport gain of magnitude sufficient to assist the injection of carriers into the floating body region, yet small enough to guard against inter-latching with the MOSFET.

Abstract: A new memory cell can contain only a single thyristor. There is no need to include an access transistor in the cell. In one embodiment, the thyristor is a thin capacitively coupled thyristor. The new memory cell can be connected to word, bit, and control lines in several ways to form different memory arrays. Timing and voltage levels of word, bit and control lines are disclosed.

Abstract: A dynamically-operating restoration circuit is used to apply a voltage or current restore pulse signal to thyristor-based memory cells and therein restore data in the cell using the internal positive feedback loop of the thyristor. In one example implementation, the internal positive feedback loop in the thyristor is used to restore the conducting state of a device after the thyristor current drops below the holding current. A pulse and/or periodic waveform are defined and applied to ensure that the thyristor is not released from its conducting state. The time average of the periodic restore current in the thyristor may be lower than the holding current threshold. While not necessarily limited to memory cells that are thyristor-based, various embodiments of the invention have been found to be the particularly useful for high-speed, low-power memory cells in which a thin capacitively-coupled thyristor is used to provide a bi-stable storage element.

Abstract: State maintenance of a memory cell and, more particularly, state maintenance pulsing of identified memory cells more frequently than other memory cells, is described. A memory array includes an array of memory cells. State maintenance circuitry is coupled to the array of memory cells. The state maintenance circuitry is configured to select between a first restore address and a second restore address. In a given operation cycle, the first restore address is associated with a first line in the array of memory cells, and the second restore address is associated with a second line in the array of memory cells. The first line has first memory cells coupled thereto. The second line has second memory cells coupled thereto. The first memory cells are capable of passing a threshold retention time with a first frequency of restore cycling. The second memory cells are capable of passing the threshold retention time with a second frequency of restore cycling.

Abstract: 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.