A semiconductor device includes: a semiconductor substrate having a first surface and a second surface; a first insulation separation region disposed on the first surface of the semiconductor substrate; a second insulation separation region surrounded with the first insulation separation region and electrically isolated from the first insulation separation region; a semiconductor element disposed in the second insulation separation region; and an electrode connecting to the first insulation separation region for energizing and generating heat in the first insulation separation region. The first insulation separation region functions as a heater so that the semiconductor element in the second insulation separation region is locally heated.