Semiconductor devices are formed using a thin epitaxial layer (nanotube) formed on sidewalls of dielectric-filled trenches. In one embodiment, a method for forming a semiconductor device includes forming a first epitaxial layer on sidewalls of trenches and forming second epitaxial layer on the first epitaxial layer where charges in the doped regions along the sidewalls of the first and second trenches achieve charge balance in operation. In another embodiment, the semiconductor device includes a termination structure including an array of termination cells.

A semiconductor device includes a plurality of drift regions of a vertical field effect transistor arrangement arranged in a semiconductor substrate. The plurality of drift regions has a first conductivity type. The semiconductor device further includes a plurality of compensation regions arranged in the semiconductor substrate. The plurality of compensation regions has a second conductivity type. Each drift region of the plurality of drift regions is arranged adjacent to at least one compensation region of the plurality of compensation regions. The semiconductor device further includes a body region of a transistor structure of the vertical field effect transistor arrangement arranged adjacent to a drift region of the plurality of drift regions. The semiconductor device further includes a gate extending substantially vertically along the body region of the transistor structure for controlling a substantially vertical channel region between a first doping region of the transistor structure and the drift region.

A semiconductor device including a mesa portion formed on a front surface side of a semiconductor substrate; a floating portion formed on the front surface side of the semiconductor substrate; a trench formed surrounding the floating portion and separating the mesa portion from the floating portion; an electrode formed inside the trench; and an outside wiring portion formed along an arrangement direction of the mesa portion and the floating portion, outside the region surrounded by the trench. An edge of the outside wiring portion on the mesa portion and floating portion side includes a protruding portion formed in at least part of a region opposite the floating portion and protruding beyond the trench toward the floating portion side, and a recessed portion formed in at least part of a region opposite the mesa portion and recessed to the outside wiring portion side farther than the protruding portion.

An IGBT has an emitter region, a top body region that is formed below the emitter region, a floating region that is formed below the top body region, a bottom body region that is formed below the floating region, a trench, a gate insulating film that covers an inner face of the trench, and a gate electrode that is arranged inside the trench. When a distribution of a concentration of p-type impurities in the top body region and the floating region, which are located below the emitter region, is viewed along a thickness direction of a semiconductor substrate, the concentration of the p-type impurities decreases as a downward distance increases from an upper end of the top body region that is located below the emitter region, and assumes a local minimum value at a predetermined depth in the floating region.

In the reverse-conducting IGBT according to the present invention, an n-type buffer layer surrounds a p-type collector layer. A p-type separation layer surrounds an n-type cathode layer. The n-type buffer layer separates the p-type collector layer and the p-type separation layer from each other. The p-type separation layer separates the n-type cathode layer and the n-type buffer layer from each other. Therefore, the present invention makes it possible to reduce snapback.

A semiconductor device includes a semiconductor substrate with: a drift layer; a base layer; and a collector layer and a cathode layer. In the semiconductor substrate, when a region operating as an IGBT device is an IGBT region and a region operating as a diode device is a diode region, the IGBT and diode regions are arranged alternately in a repetitive manner; a damaged region is arranged on a surface portion of the diode region in the semiconductor substrate. The IGBT and diode regions are demarcated by a boundary between the collector and cathode layers; and a surface portion of the IGBT region includes: a portion having the damaged region at a boundary side with the diode region; and another portion without the damaged region arranged closer to an inner periphery side relative to the boundary side.

A manufacturing method includes an implantation of impurities and laser irradiation. In the implantation, impurities are implanted to first and second areas so as to obtain a relationship that a total amount of the first impurities is larger than a total amount of the second impurities in a first depth range and a total amount of the second impurities is larger than a total amount of the first impurities in a second depth range (deeper range). In the irradiation, the first and second areas are irradiated with laser so that an energy density of the laser is larger on the second area than on the first area. A first conductivity type region is formed on the first area so as to be exposed on the surface, and a second conductivity type region is formed on the second area so as to be exposed on the surface.

A semiconductor device according to an embodiment includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, a third semiconductor layer of the first conductivity type, a fourth semiconductor layer of the second conductivity type, a first electrode connected to the second semiconductor layer and the fourth semiconductor layer, a second electrode facing the second semiconductor layer with an insulating film interposed, a fifth semiconductor layer of the second conductivity type, a sixth semiconductor layer of the first conductivity type, a seventh semiconductor layer of the second conductivity type, a third electrode connected to the fifth semiconductor layer and the seventh semiconductor layer, and a fourth electrode facing the fifth semiconductor layer with an insulating film interposed.

Provided is a semiconductor device including a semiconductor substrate; a dummy trench that is formed on a front surface side of the semiconductor substrate; an emitter electrode that is formed above a front surface of the semiconductor substrate and includes a recessed portion that is a recess in an outer periphery thereof, as seen in a planar view; a dummy pad that is electrically connected to the dummy trench and has at least a portion thereof formed within the recessed portion, as seen in the planar view; and a dummy wire that electrically connects the emitter electrode and the dummy pad.

A semiconductor device including a semiconductor substrate; a trench formed in a front surface of the semiconductor substrate; a gate conducting portion formed within the gate trench; and a first region formed adjacent to the trench in the front surface of the semiconductor substrate and having a higher impurity concentration than the semiconductor substrate. A shoulder portion is provided on a side wall of the gate trench between the top end of the gate conducting portion and the front surface of the semiconductor substrate and has an average slope, relative to a depth direction of the semiconductor substrate, that is greater than a slope of the side wall of the gate trench at a position opposite the top end of the gate conducting portion, and a portion of the first region that contacts the gate trench is formed as a deepest portion thereof.