Semiconductor device and process for its preparation

A semiconductor device which comprises: - a semiconductor substrate (10) of a first conductivity type having a first main surface and a second main surface which are opposite each other; - a first recess (22) of a second conductivity type in a top surface of a drift layer (20) formed on the first major surface in a range of cells (12) of the first major surface; - a diffusion region (24, 76) of a first conductivity type in the upper surface of the drift layer (20) in the first well (22); - a first gate insulating layer (36) on the first well (22); - a first gate electrode (38) on the first gate insulating layer (36); - a second well (28) of a second conductivity type in the upper surface of the drift layer (20) at a peripheral portion of the cell area (12); - a second gate insulating layer (40) on the second well (28); - a field oxide layer (42) on the second well (28) on the peripheral side of the second gate insulating layer (40) thicker than the second gate insulating layer (40); is a second gate electrode (44) formed on the second gate insulating layer (40) and the field oxide layer (42) is provided sequentially with the first gate electrode (38) electrically connected -; - a first electrode (14, 74) with the first well (22), the second well (28) and the diffusion region (24, 76) is electrically connected; - a second electrode (60, 78) on the second main surface of the semiconductor substrate (10); - a gate wiring (16) on the field oxide layer (42) extending around a periphery of the cell area (12) around and to the second gate electrode (44) is electrically connected; and - a gate pad (18) which is electrically connected to the gate wiring (16), - wherein the gate wiring (16) is a silicide of a constituent substance of the second gate electrode (44), and ...