Operations with reduced current overall are performed on single thyristor memory cells forming a volatile memory cell cross-point array. An operation is performed on at least one memory cell in a first group of memory cells out of a plurality of groups of memory cells coupled to a line. A first voltage is applied across the first group of memory cells for the operation and a lower second voltage is applied across the other groups of memory cells. The first voltage is then applied across a second group of memory cells while the second voltage is applied across the other groups including the first group of memory cells. These steps may repeated until the operations covers all the groups.

Memory cells are formed with vertical thyristors to create a volatile memory array. Power consumption in such arrays is reduced or controlled with various techniques including encoding the data stored in the arrays.

In an example, a semiconductor device includes a semiconductor substrate of a first conductivity type and a semiconductor region of the first conductivity type over the semiconductor substrate. A well region of a second conductivity type is in the semiconductor region. A doped region of the first conductivity type is in the well region. A doped region of the second conductivity type is in the well region. A doped region of the second conductivity type is in the semiconductor substrate at a bottom side. A doped region of the first conductivity type is in the semiconductor substrate at the bottom side. A first conductor is at a top side of the semiconductor region and a second conductor is at the bottom side. In some examples, one or more of doped regions at the bottom side is a patterned doped region.

An insulated gate turn-off (IGTO) device, formed as a die, has a layered structure including a P+ layer (e.g., a substrate), an N epi layer, a P-well, vertical insulated gates formed in the P-well, and N+ regions between at least some of the gates, so that vertical NPN and PNP transistors are formed. A source/emitter electrode is on top, and a drain/cathode electrode is on the bottom of the substrate. The device is formed of a matrix of cells. To turn the device on, a positive voltage is applied to the gates, referenced to the source/emitter electrode. Some of the cells are passive, having gates that are either not connected to the active gates or having gates that are shorted to their associated N+ regions, to customize the input capacitance and lower the saturation current. Other techniques are described to form the passive cells.

The invention relates to a bipolar non-punch-through power semiconductor device and a corresponding manufacturing method. The device comprises a semiconductor wafer and a first electrode formed on a first main side of the wafer and a second electrode formed on a second main side of the wafer opposite the first main side. The wafer comprises a pair of layers of different conductivity types, such as a drift layer of a first conductivity type, and a first layer of a second conductivity type arranged on the drift layer towards the first main side and contacting the first electrode. The wafer comprises an inner region wand an outer region surrounding the inner region. The drift layer has a thickness in the inner region greater or equal than a thickness in the outer region. A thickness of the first layer increases in a transition region between the inner region and the outer region from a thickness in the inner region to a maximum thickness in the outer region. The thickness of the first layer increases linearly over the transition region with a width of the transition region greater than 5 times a thickness of the first section of the first layer.

The invention relates to a turn-off power semiconductor device comprising a plurality of thyristor cells, each thyristor cell comprising a cathode region; a base layer; a drift layer; an anode layer; a gate electrode which is arranged lateral to the cathode region in contact with the base layer; a cathode electrode; and an anode electrode. Interfaces between the cathode regions and the cathode electrodes as well as interfaces between the base layers and the gate electrodes of the plurality of thyristor cells are flat and coplanar. In addition, the base layer includes a gate well region extending from its contact with the gate electrode to a depth, which is at least half of the depth of the cathode region, wherein, for any depth, the minimum doping concentration of the gate well region at this depth is 50% above a doping concentration of the base layer between the cathode region and the gate well region at this depth and at a lateral position, which has in an orthogonal projection onto a plane parallel to the first main side a distance of 2 m from the cathode region. The base layer includes a compensated region of the second conductivity type, the compensated region being arranged directly adjacent to the first main side and between the cathode region and the gate well region, wherein the density of first conductivity type impurities relative to the net doping concentration in the compensated region is at least 0.4.

In an example, a semiconductor device includes a semiconductor substrate of a first conductivity type and a semiconductor region of the first conductivity type over the semiconductor substrate. A well region of a second conductivity type is in the semiconductor region. A doped region of the first conductivity type is in the well region. A doped region of the second conductivity type is in the well region. A doped region of the second conductivity type is in the semiconductor substrate at a bottom side. A doped region of the first conductivity type is in the semiconductor substrate at the bottom side. A first conductor is at a top side of the semiconductor region and a second conductor is at the bottom side. In some examples, one or more of doped regions at the bottom side is a patterned doped region.

Trenches having a gate oxide layer are formed in the surface of a silicon wafer for vertical gates. Conductive doped polysilicon is then deposited in the trenches to form a relatively thin layer of doped polysilicon along the sidewalls. Thus, there is a central cavity surrounded by polysilicon. Next, the cavity is filled in with a much higher conductivity material, such as aluminum, copper, a metal silicide, or other conductor to greatly reduce the overall resistivity of the trenched gates. The thin polysilicon forms an excellent barrier to protect the gate oxide from diffusion from the inner conductor atoms. The inner conductor and the polysilicon conduct the gate voltage in parallel to lower the resistance of the gates, which increases the switching speed of the device. In another embodiment, a metal silicide is used as the first layer, and a metal fills the cavity.

Memory cells are formed with vertical thyristors to create a volatile memory array. Power consumption in such arrays is reduced or controlled with various techniques including encoding the data stored in the arrays.

There is provided a thyristor having emitter shorts, wherein in an orthogonal projection onto a plane parallel to a first main side, a contact area covered by an electrical contact of a first electrode layer with a first emitter layer and the emitter shorts includes areas in the shape of lanes, in which an area coverage of the emitter shorts is less than the area coverage of emitter shorts in the remaining area of the contact area, wherein the area coverage of the emitter shorts in a specific area is the area covered by the emitter shorts in that specific area relative to the specific area. The thyristor of the invention exhibits a fast turn-on process even without complicated amplifying gale structure.