Methods and systems for reducing electrical disturb effects between thyristor memory cells in a memory array are provided. Electrical disturb effects between cells are reduced by using a material having a reduced minority carrier lifetime as a cathode line that is embedded within the array. Disturb effects are also reduced by forming a potential well within a cathode line, or a one-sided potential barrier in a cathode line.

An insulated gate turn-off thyristor has a layered structure including a p+ layer (e.g., a substrate), an n-epi layer, a p-well, vertical insulated gate regions formed in the p-well, and an n-layer over the p-well and between the gate regions, so that vertical npn and pnp transistors are formed. The p-well has an intermediate highly doped portion. When the gate regions are sufficiently biased, an inversion layer surrounds the gate regions, causing the effective base of the npn transistor to be narrowed to increase its beta. When the product of the betas exceeds one, controlled latch-up of the thyristor is initiated. The p-well's highly doped intermediate region enables improvement in the npn transistor efficiency as well as enabling more independent control over the characteristics of the n-type layer (emitter), the emitter-base junction characteristics, and the overall dopant concentration and thickness of the p-type base.

Apparatus and methods for reducing minority carriers in a memory array are described herein. Minority carriers diffuse between ON cells and OFF cells, causing disturbances during write operation as well as reducing the retention lifetime of the cells. Minority Carrier Lifetime Killer (MCLK) region architectures are described for vertical thyristor memory arrays with insulation trenches. These MCLK regions encourage recombination of minority carriers. In particular, MCLK regions formed by conductors embedded along the cathode line of a thyristor array, as well as dopant MCLK regions are described, as well as methods for manufacturing thyristor memory cells with MCLK regions.

Methods and systems for reducing electrical disturb effects between thyristor memory cells in a memory array are provided. Electrical disturb effects between cells are reduced by using a material having a reduced minority carrier lifetime as a cathode line that is embedded within the array. Disturb effects are also reduced by forming a potential well within a cathode line, or a one-sided potential barrier in a cathode line.

A semiconductor device, in which, in a density distribution of first conductivity type impurities in the first conductivity type region measured along a thickness direction of the semiconductor substrate, a local maximum value N1, a local minimum value N2, a local maximum value N3, and a density N4 are formed in this order from front surface side, a relationship of N1>N3>N2>N4 is satisfied, a relationship of N3/10>N2 is satisfied, and a distance a from the surface to the depth having the local maximum value N1 is larger than twice a distance b from the depth having the local maximum value N1 to the depth having the local minimum N2.

A semiconductor device includes stripe-shaped gate trench formed in one major surface of n-type drift layer, gate trench including gate polysilicon formed therein, and gate polysilicon being connected to a gate electrode; p-type base layer formed selectively in mesa region between adjacent gate trenches, p-type base layer including n-type emitter layer and connected to emitter electrode; one or more dummy trenches formed between p-type base layers adjoining to each other in the extending direction of gate trenches; and electrically conductive dummy polysilicon formed on an inner side wall of dummy trench with gate oxide film interposed between dummy polysilicon and dummy trench, dummy polysilicon being spaced apart from gate polysilicon. Dummy polysilicon may be connected to emitter electrode. The structure according to the invention facilitates providing an insulated-gate semiconductor device, the Miller capacitance of which is small, even when the voltage applied between the collector and emitter is low.

A semiconductor device, in which, in a density distribution of first conductivity type impurities in the first conductivity type region measured along a thickness direction of the semiconductor substrate, a local maximum value N1, a local minimum value N2, a local maximum value N3, and a density N4 are formed in this order from front surface side, a relationship of N1>N3>N2>N4 is satisfied, a relationship of N3/10>N2 is satisfied, and a distance a from the surface to the depth having the local maximum value N1 is larger than twice a distance b from the depth having the local maximum value N1 to the depth having the local minimum N2.

A RC power semiconductor is provided which comprises a plurality of diode cells and a plurality of GCT cells. Each GCT cell comprises a first cathode layer with at least three cathode layer regions, which are separated from each other by a base layer. In orthogonal projection onto a plane parallel to the first main side each one of the cathode layer regions is strip-shaped and a width (w, w), wherein the diode cells alternate with the GCT cells in a lateral direction in at least a mixed part, wherein in each GCT cell, the width (w) of each one of the two outer cathode layer regions next to a diode cell neighboring to that GCT cell is less than the width (w) of any intermediate cathode layer region between the two outer cathode layer regions in that GCT cell.

Provided is an imaging element including a photoelectric conversion unit formed by stacking a first electrode, a photoelectric conversion layer and a second electrode. The photoelectric conversion unit further includes a charge storage electrode which is disposed to be spaced apart from the first electrode and disposed opposite to the photoelectric conversion layer via an insulating layer. The photoelectric conversion unit is formed of N number of photoelectric conversion unit segments, and the same applies to the photoelectric conversion layer, the insulating layer and the charge storage electrode. An n.sup.th photoelectric conversion unit segment is formed of an n.sup.th charge storage electrode segment, an n.sup.th insulating layer segment and an n.sup.th photoelectric conversion layer segment. As n increases, the n.sup.th photoelectric conversion unit segment is located farther from the first electrode. A thickness of the insulating layer segment gradually changes from a first to N.sup.th photoelectric conversion unit segment.

Disclosed is a power semiconductor device comprising a semiconductor wafer having a first main side and second main side. The semiconductor wafer comprises parallel thyristor cells, which each comprises (a) a cathode electrode and gate electrode on the first main side; (b) a cathode layer comprising a cathode region of a first conductivity type, forming an ohmic contact with the cathode electrode; (c) a first base layer of a second conductivity type, wherein the cathode region forms a p-n junction between the first base layer and cathode region; (d) a second base layer of the first conductivity type forming a second p-n junction with the first base layer; (e) an anode layer of the second conductivity type separated from the first base layer by the second base layer. The gate electrodes of the plurality of thyristor cells form a gate design comprising multiple polygons each comprising at least four struts.