The subject matter disclosed herein relates to semiconductor power devices, such as silicon carbide (SiC) power devices. In particular, the subject matter disclosed herein relates to shielding regions in the form of body region extensions for that reduce the electric field present between the well regions of neighboring device cells of a semiconductor device under reverse bias. The disclosed body region extensions have the same conductivity-type as the body region and extend outwardly from the body region and into the JFET region of a first device cell such that a distance between the body region extension and a region of a neighboring device cell having the same conductivity type is less than or equal to the parallel JFET width. The disclosed shielding regions enable superior performance relative to a conventional stripe device of comparable dimensions, while still providing similar reliability (e.g., long-term, high-temperature stability at reverse bias).

A design technique is disclosed that divides up a cellular power switch into different size segments. Each segment is driven by a different driver circuit. The selection of the combination of segments is made to minimize the combined conduction and switching losses of the power switch. For example, for very light loads, switching losses dominate so only a small segment is activated for driving the load. For medium and high load currents, conduction losses become more significant, so additional segments are activated to minimize the total losses. In one embodiment, the number of cells in the segments is binary weighted, such as 1×, 2×, and 4×, so that there are seven different combinations of segments. The drivers may be configured to achieve the same or different slew rates of the segments, such as to reduce transients. The segments may all be in the same die or a plurality of dies.

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 p-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.

A trenched, vertical MOS-gated switch is described that uses only three or four masking steps to fabricate. In one embodiment, one mask is used to form first trenches having a first depth, wherein the first trenches are filled with doped polysilicon to form gates to control the conduction of the switch. A second mask is used to form second trenches having a shallower second depth. The second trenches are filled with the same metal used to form the top source electrode and gate electrode. The metal filling the second trenches electrically contacts a top source layer and a body region. A third mask is used to etch the metal to define the source metal, the gate electrode, and floating rings in a termination region surrounding the active area of the switch. An additional mask may be used to form third trenches in the termination region that are deeper than the first trenches.

The present invention forms an off-FET channel having a uniform and short length by using a self-align process of a method of forming and recessing a spacer, thereby enhancing the current driving capability of an off-FET and the uniformity of a device operation.

A power diode comprises a plurality of diode cells (10). Each diode cell (10) comprises a first conductivity type first anode layer (40), a first conductivity type second anode layer (45) having a lower doping concentration than the first anode layer (40) and being separated from an anode electrode layer (20) by the first anode layer (40), a second conductivity type drift layer (50) forming a pn-junction with the second anode layer (45), a second conductivity type cathode layer (60) being in direct contact with the cathode electrode layer (60), and a cathode-side segmentation layer (67) being in direct contact with the cathode electrode layer (30). A material of the cathode-side segmentation layer (67) is a first conductivity type semiconductor, wherein an integrated doping content of the cathode-side, which is integrated along a direction perpendicular to the second main side (102), is below 2.Math.10.sup.13 cm.sup.−2, or a material of the cathode-side segmentation layer (67) is an insulating material. A horizontal cross-section through each diode cell (10) along a horizontal plane (K1) comprises a first area where the horizontal plane (K1) intersects the second anode layer (45) and a second area where the plane (K1) intersects the drift layer (50).

The disclosure provides dyes for marking hydrocarbon compositions. More particularly, the disclosure relates to non-mutagenic dyes for marking hydrocarbon com positions.

A MOS controlled thyristor device according to the concept of the present invention includes a substrate comprising a first surface and a second surface, which face each other, gate patterns disposed on the first surface, a cathode electrode configured to cover the gate patterns, and an anode electrode disposed on the second surface, The substrate includes a lower emitter layer having a first conductive type, a lower base layer having a second conductive type on the lower emitter layer, an upper base region provided in an upper portion of the lower emitter layer and having a first conductive type, wherein the upper base region is configured to expose a portion of a top surface of the lower base layer, an upper emitter region having a second conductive type and provided in an upper portion of the upper base region, a first doped region having a first conductive type and a second doped region surrounded by the first doped region and having a second conductive type, wherein the first and second doped regions are provided in an upper portion of the upper emitter region, and a first doping pattern having a first conductive type, which is provided on one surface of the upper portion of the upper emitter region. The first doping pattern is interposed between the upper base region and the first doped region along a first direction parallel to the top surface of the substrate. The first doping pattern is configured to expose a top surface of the upper emitter region on the other surface of the upper portion of the upper emitter region. Each of the gate patterns is configured to cover portions of an exposed top surface of the lower base layer, an exposed top surface of the upper base layer, an exposed top surface of the upper emitter region, a top surface of the first doping pattern, and a top surface of the first doped region. The cathode electrode is configured to cover portions of top and side surfaces of the gate pattern, a top surface of the second doped region, and a top surface of the first doped region. The first conductive type and the second conductive type are different from each other.

A method of manufacturing a semiconductor integrated circuit, includes: forming a first well region having a second conductivity type in an upper portion of a support layer having a first conductivity type; forming an oxide film on the first well region by a thermal oxidation method to decrease a concentration of impurities at an top surface of top surface side of the first well region; removing the oxide film; forming a second well region having the first conductivity type in an upper portion of the first well region; and merging a semiconductor element having a main electrode region having the second conductivity type in the second well region.

After the various regions of a vertical power device are formed in or on the top surface of an n-type wafer, the wafer is thinned, such as by grinding. A drift layer may be n-type, and various n-type regions and p-type regions in the top surface contact a top metal electrode. A blanket dopant implant through the bottom surface of the thinned wafer is performed to form an n− buffer layer and a bottom p+ emitter layer. Energetic particles are injected through the bottom surface to intentionally damage the crystalline structure. A wet etch is performed, which etches the damaged crystal at a much greater rate, so some areas of the n− buffer layer are exposed. The bottom surface is metallized. The areas where the metal contacts the n− buffer layer form cathodes of an anti-parallel diode for conducting reverse voltages, such as voltage spikes from inductive loads.