SEMICONDUCTOR DEVICE

摘要

A resistor for detecting a current is connected between a source electrode (25) of a main element (24) and a current sensing electrode (22) of a current detecting element (21). The withstand voltage of a gate insulating film (36) is larger than a product of the maximum current, which can be carried to the current detecting element (21) when reversely biased, and the resistance. The diffusion depth of a p-body region (32) of the main element (24) is less than that of a p-body region (31) of the current detecting element (21), and the curvature at an end section of the p-body region (32) of the main element (24) is smaller than that at an end section of the p-body region (31) of the current detecting element (21). Thus, when reverse bias is applied, an electric field at the end section of the p-body region (32) of the main element (24) becomes higher than that at the end section of the p-body region (31) of the current detecting element (21), and avalanche breakdown is permitted to easily occur in the main element (24) prior to that in the current detecting element (21).