A semiconductor device according to the present disclosure includes: a trench located in a semiconductor substrate on a side of a front surface thereof to extend through a base layer, the trench including a top electrode covered with a top oxide film, a bottom electrode covered with a bottom oxide film, and a boundary oxide film located between the top electrode and the bottom electrode, wherein a surface of the top electrode facing the bottom electrode has a recessed shape and includes a prong forming the recessed shape, the prong extends in a width direction of the trench, the prong and the bottom electrode face each other in the width direction of the trench, the top oxide film has a constant film thickness along the base layer and a layer underlying the base layer, and the boundary oxide film has a greater film thickness than the top oxide film.

A semiconductor device includes: a channel stopper region of a first conductivity type formed on a surface layer of a drift layer in a termination region; a first termination trench formed in the drift layer in the termination region; a plurality of termination electrodes provided in the first termination trench while being surrounded by a first termination insulating film; and a channel stopper electrode provided on an upper surface of the drift layer while being electrically connected to the channel stopper region and the termination electrodes, wherein the plurality of termination electrodes include a first termination electrode and a second termination electrode.

A semiconductor device includes a chip that has a first principal surface and a second principal surface on an opposite side thereto, a first impurity region of a first conductivity type that is formed in a surface layer portion of the first principal surface, a second impurity region of a second conductivity type that is formed in a surface layer portion of the first impurity region, a third impurity region of the first conductivity type that is formed in a surface layer portion of the second impurity region, a plurality of trenches that reach the first impurity region through the third impurity region and the second impurity region from the first principal surface, and an electric field relaxation structure of the second conductivity type that is formed integrally with the second impurity region and straddles bottom walls of the plurality of trenches.

A semiconductor device includes a semiconductor layer of a first conductivity type provided in an active region and a termination region and a channel stop portion provided inside an outer end portion of the termination region, in which the channel stop portion includes a first channel stop groove portion formed to reach the inside from an upper surface of the semiconductor layer, a first impurity portion of the first conductivity type formed in a surface layer of the semiconductor layer outside the first channel stop groove portion, and a second impurity portion of the first conductivity type formed in a bottom portion of the first channel stop groove portion, and impurity concentrations of the first and second impurity portions are higher than that of the semiconductor layer.

A semiconductor device includes an active area and a junction termination area, each including a drain electrode, a first epitaxial layer of a first conductivity type disposed on the drain electrode, and a second epitaxial layer of the first conductivity type disposed on the first epitaxial layer. The junction termination area further includes a first junction termination area etched on a portion of the second epitaxial layer, and a second junction termination area that is not etched. A field oxide layer is disposed on a portion of the first junction termination area. A doped region of a second conductivity type is disposed to extend from beneath the field oxide layer to the second junction termination area.