Semiconductor strain gauge

摘要

A semiconductor strain gauge is arranged as a bridge having four piezoresistive elements which each include a low impurity concentration diffused portion and a heavily-doped diffused portion. The resistance values of the two low impurity concentration diffused portions opposite each other in the bridge are greater than the resistance values of the other two lower impurity concentration portions. The resistances of the heavily-doped diffused portion are selected so that the resistance of the piezoresistive elements are equal. However, by virtue of the fact that the resistance temperature coefficient of the low impurity portions are greater than the resistance temperature coefficients of the high impurity portions, the overall resistance temperature coefficients of the bridge arms will be different. This permits the zero-point voltage of the bridge to always increase with an increase in temperature.