A semiconductor device includes a chip that has a main surface, a high concentration region of a first conductivity type that is formed in a surface layer portion of the main surface on an inner portion side of the chip, and a low concentration region of the first conductivity type that is formed in the surface layer portion of the main surface on a peripheral edge portion side of the chip, and has an impurity concentration lower than an impurity concentration of the high concentration region.

A semiconductor device includes a main element and a sensing element each including a drift region of a first conductivity-type, a well region of a second conductivity-type provided at an upper part of the drift region, a first main electrode region of the first conductivity-type provided at an upper part of the well region, a gate electrode buried with a gate insulating film interposed in a trench, and a main electrode connected to the first main electrode region, the isolation region including an element-isolation insulating film provided on a top surface of a semiconductor base body interposed between the well regions, and a first wire provided on a top surface of the element-isolation insulating film and electrically connected to the main electrode of the main element.

First and second buffer regions and an n.sup.-type drift region are sequentially formed by epitaxial growth on an n.sup.+-type starting substrate. An impurity concentration of the first buffer region is higher than that of the n.sup.-type drift region and lower than that of the n.sup.+-type starting substrate. An impurity concentration of the second buffer region is higher than that of the first buffer region and continuously increases by a first impurity concentration gradient from a first gradient changing point toward the n.sup.-type drift region to a second gradient changing point toward the first buffer region; continuously decreases by a second impurity concentration gradient from the first gradient changing point to a first interface; and continuously decreases by a third impurity concentration gradient from the second gradient changing point to a second interface. The second impurity concentration gradient is lower than the third impurity concentration gradient.

A semiconductor device of an embodiment includes a SiC layer including a first face parallel to first direction and second direction perpendicular to the first direction, a trench extending in the first direction, a gate electrode, an n-type first SiC region, a p-type second SiC region between the first SiC region and the trench, extending in the second direction, an n-type third SiC region extending in the second direction, and alternately and repeatedly provided with the second SiC region in the first direction, a p-type fourth SiC region between the third SiC region and the first face, an n-type fifth SiC region between the fourth SiC region and the first face. The first face is inclined with respect to a (0001) face by 0.1 to 8 degrees in a <11-20> direction, and the first direction is along the <11-20> direction, and the second direction is along a <1-100> direction.