Abstract: A p-type nitride compound semiconductor layer is formed on a buffer formed on a substrate. An n-type contact region is formed by ion implantation under a source electrode and a drain electrode. An electric-field reducing layer made of an n-type nitride compound semiconductor is formed on the p-type nitride compound semiconductor layer. A carrier density of the electric-field reducing layer is lower than that of the n-type contact region. A first end portion of the electric-field reducing layer contacts with the n-type contact region, and a second end portion of the electric-field reducing layer overlaps with a gate electrode.

Abstract: An HEMT type transistor is disclosed that is a normally off type, and in which variations in the gate threshold voltage are small. A transistor is provided with a p-type region, a barrier region, an insulation film, a gate electrode. The channel region is connected to an upper surface of the p-type region. The channel region is n-type or i-type and provided with a first channel region and a second channel region. The barrier region is forming a hetero-junction with an upper surface of the first channel region. The insulation film is connected to an upper surface of the second channel region and an upper surface of the barrier region. The gate electrode faces the second channel region and the barrier region via the insulation film. The first channel region and the second channel region are arranged in series in a current pathway.

Abstract: In one aspect, a lateral MOS device is provided. The lateral MOS device includes a gate electrode disposed at least partially in a gate trench to apply a voltage to a channel region, and a drain electrode spaced from the gate electrode, and in electrical communication with a drift region having a boundary with a lower end of the channel region. The device includes a gate dielectric layer in contact with the gate electrode, and disposed between the gate electrode and the drain electrode. The channel region is adjacent to a substantially vertical wall of the gate trench. The device includes a field plate contacting the gate electrode and configured to increase a breakdown voltage of the device.

Abstract: A p-type nitride compound semiconductor layer is formed on a buffer formed on a substrate. An n-type contact region is formed by ion implantation under a source electrode and a drain electrode. An electric-field reducing layer made of an n-type nitride compound semiconductor is formed on the p-type nitride compound semiconductor layer. A career density of the electric-field reducing layer is lower than that of the n-type contact region. A first end portion of the electric-field reducing layer contacts with the n-type contact region, and a second end portion of the electric-field reducing layer overlaps with a gate electrode.

Abstract: In one aspect, a lateral MOS device is provided. The lateral MOS device includes a gate electrode disposed at least partially in a gate trench to apply a voltage to a channel region, and a drain electrode spaced from the gate electrode, and in electrical communication with a drift region having a boundary with a lower end of the channel region. The device includes a gate dielectric layer in contact with the gate electrode, and disposed between the gate electrode and the drain electrode. The channel region is adjacent to a substantially vertical wall of the gate trench. The device includes a field plate contacting the gate electrode and configured to increase a breakdown voltage of the device.

Abstract: An HEMT type transistor is disclosed that is a normally off type, and in which variations in the gate threshold voltage are small. A transistor is provided with a p-type region, a barrier region, an insulation film, a gate electrode. The channel region is connected to an upper surface of the p-type region. The channel region is n-type or i-type and provided with a first channel region and a second channel region. The barrier region is forming a hetero-junction with an upper surface of the first channel region. The insulation film is connected to an upper surface of the second channel region and an upper surface of the barrier region. The gate electrode faces the second channel region and the barrier region via the insulation film. The first channel region and the second channel region are arranged in series in a current pathway.

Abstract: A semiconductor device includes a graded junction termination extension. A method for fabricating the device includes providing a semiconductor layer having a pn junction, providing a mask layer adjacent to the semiconductor layer, etching the mask layer to form at least two laterally adjacent steps associated with different mask thicknesses and substantially planar step surfaces, and implanting a dopant species through the mask layer into a portion of the semiconductor layer adjacent to the termination of the pn junction. The semiconductor layer is annealed to activate at least a portion of the implanted dopant species to form the graded junction termination extension.

Abstract: Doping of the P type base region in a MOSFET or an IGBT with a combination of boron and one or more of indium, aluminum and gallium, provides a structure having a lower P type doping level in the channel portion of the structure than in the remainder of the structure without requiring counter doping of the channel. The doping level of the emitter region of an MCT is kept high everywhere except in the channel in order to provide a fast turn-off time for the MCT.

Abstract: A semiconductor device includes a semiconductor substrate having an epitaxial layer surface opposite a drain contact surface; a semiconductor layer adjacent to the epitaxial layer surface of the substrate, the semiconductor layer including material of a first conductivity type; a patterned refractory dielectric layer adjacent to the semiconductor layer; a base region of implanted ions in the semiconductor layer, the base region being of a second conductivity type; a source region of implanted ions in the base region, the source region being of the first conductivity type; a gate insulator layer adjacent to at least a portion of the source and base regions of the semiconductor layer; and a gate electrode over a portion of the gate insulator layer, adjacent to and in physical contact with an outer edge of the patterned refractory dielectric layer, and over at least a portion of the base region between the source region and the patterned refractory dielectric layer.