A semiconductor structure includes a substrate having a first surface and a second surface opposite to the first surface. The semiconductor structure also includes a first diffusion layer disposed in the substrate and adjacent to the first surface, and a first electrode layer disposed on the first diffusion layer. The semiconductor structure further includes a second diffusion layer disposed in the substrate and adjacent to the second surface, and a plurality of diffusion regions disposed in the second diffusion layer. The semiconductor structure further includes a second electrode layer disposed on the second diffusion layer and in contact with the plurality of diffusion regions. The second diffusion layer is coupled to the plurality of diffusion regions through the second electrode layer. The substrate is sandwiched between the first electrode layer and the second electrode layer.

An electrostatic discharge (ESD) protection device including: a substrate including: a first, second and third doped regions, the second doped region disposed between the first and third doped regions, the second doped region has a first conductivity type and a first doping concentration and the first and third doped regions have a second conductivity type and a second doping concentration; first and second doped terminal regions disposed within the first and second doped regions, respectively; and a doped island region disposed within the second doped region, the first and second doped terminal regions and doped island region have the second conductivity type and a third doping concentration, the third doping concentration higher than the first and second doping concentrations; and conductive terminals respectively coupled to the doped terminal regions; and an insulation layer arranged on the substrate between the conductive terminals and covering at least the second doped region.

In one embodiment, an asymmetric TVS device may include a semiconductor substrate, comprising an inner region, the inner region having a first polarity, and a first surface region, disposed on a first surface of the semiconductor substrate, the first surface region comprising a second polarity, opposite the first polarity. The asymmetric TVS device may also include a second surface region, comprising the second polarity, and disposed on a second surface of the semiconductor substrate, opposite the first surface, wherein the first surface region comprises a first dopant concentration, and wherein the second surface region comprises a second dopant concentration, greater than the first dopant concentration.

Process flow for a stacked power diode and design of the resulting diode is disclosed. Blanket epitaxy over heavy doped wafers is performed. By controlling dopant addition during epitaxy, desired n-type, diode base, and p-type doping profiles and thicknesses achieved. V-groove pattern if formed on wafers by depositing mask film, lithography and anisotropic etch. Islands surrounded by V-grooves define individual diodes. V-grooves serve as side insulation. Next, oxidation step passivates V-grooves. Further, the mask film is stripped to open diode contact areas on both sides of wafers. Next high melting point metal and low melting point metal films are selectively electroplated on all open silicon surfaces. Stacking is performed on wafer level by bonding of desired wafer count by solid-liquid interdiffusion process. Wafer stacks are sawed into individual stacked diode dies along outer slopes of V-grooves. Final stacked devices can be used as DSRD—drift step recovery diodes. Compared to DSRDs made by known methods, better fabrication yield and higher pulse power electrical performance is achieved.

An electrostatic discharge (ESD) protection device is provided. The ESD protection device includes a substrate, an active region, a first terminal region, and a second terminal region. The substrate includes dopants having a first dopant conductivity. The active region is arranged over the substrate and has an upper surface. The first terminal region and the second terminal region are arranged in the active region laterally spaced apart from each other. The first terminal region and the second terminal region each include a well region having dopants of the first dopant conductivity and a first doped region arranged in the well region. The first doped region includes dopants having a second dopant conductivity.

In one general embodiment, a structure includes a first diode, comprising: a first layer having a first type of dopant, and a second layer above the first layer, the second layer having a second type of dopant that is opposite to the first type of dopant. A second diode is formed directly on the first diode. The second diode comprises a first layer having a third type of dopant and a second layer above the first layer of the second diode, the second layer of the second diode having a fourth type of dopant that is opposite to the third type of dopant. In another general embodiment, a process includes a repeated sequence of growing a first layer having a first type of electrically active dopant and growing a second layer having a second type of electrically active dopant that is opposite to the first type of dopant.

The present invention relates to a vertical semiconductor device such as an IGBT or a diode which includes an N buffer layer formed in the undersurface of and adjacent to an N.sup.− drift layer. A concentration slope δ, which is derived from displacements in a depth TB (μm) and an impurity concentration CB (cm.sup.−3), from the upper surface to the lower surface in a main portion of the N buffer layer satisfies a concentration slope condition defined by {0.03≦δ≦0.7}.

A gallium nitride power device, including: a gallium nitride substrate; cathodes; a plurality of gallium nitride protruding structures arranged on the gallium nitride substrate and between the cathodes, a groove is formed between adjacent gallium nitride protruding structures; an electron transport layer, covering a top portion and side surfaces of each of the gallium nitride protruding structures; a gallium nitride layer, arranged on the electron transport layer and filling each of the grooves; a plurality of second conductivity type regions, where each of the second conductivity type regions extends downward from a top portion of the gallium nitride layer into one of the grooves, and the top portion of each of the gallium nitride protruding structures is higher than a bottom portion of each of the second conductivity type regions; and an anode, arranged on the gallium nitride layer and the second conductivity type regions.

A bipolar semiconductor device includes at least a four-layer structure, a first main side with a first electrical contact, and a second main side with a second electrical contact separated from the first main side by at least a base layer of first conductivity type. A shorting layer of the first conductivity type is arranged on the second main side of the base layer. A third layer includes a patterned highly conductive material, such as metal and/or silicides, graphene, etc., and is deposited on the shorting. A fourth layer of the second conductivity type is arranged directly on the third layer, inserted between the shorting layer and the second electrical contact. This concept can be applied to any non-punch-through or punch-through reverse conducting IGBT designs, but is particularly effective for devices using thin wafers, and is also applicable to bipolar diodes in order to improve a soft recovery process.

An electrostatic discharge protection structure includes: substrate of a first type of conductivity, well region of a second type of conductivity, substrate contact region in the substrate and of the first type of conductivity, well contact region in the well region and of the second type of conductivity, substrate counter-doped region between the substrate contact region and the well contact region and of the second type of conductivity, well counter-doped region between the substrate contact region and the well contact region and of the first type of conductivity, communication region at a lateral junction between the substrate and the well region, first isolation region between the substrate counter-doped region and the communication region, second isolation region between the well counter-doped region and the communication region, oxide layer having one end on the first isolation region and another end on the substrate, and field plate structure on the oxide layer.