SENSOR ELEMENT FOR SEMICONDUCTOR PRESSURE SENSOR

PURPOSE:To efficiently perform temperature compensation, to improve the mass-production and to reduce the cost by forming gauge resistance parts composed of diffusion layers which differ in surface impurity density on the surface of a semiconductor diaphragm. CONSTITUTION:The output voltage V when a Wheatstone bridge circuit is constituted of gauge resistance parts R1, R2, r3, and r4 and is driven with a constant current is as shown by an equation. In the voltage state of the semiconductor diaphragm 1, the resistance parts R1 and r3 of the center part of the diaphragm 1 are so set as to satisfy R1=R+DELTAR and r3=r+DELTAr and the gauge resistance part R2 and r4 of the peripheral part are so set as to satisfy R2=R-DELTAR and r4=r-DELTAr. Then DELTAR has a negative temperature characteristics because of diffusion layers 2 and 3 with low surface impurity density, DELTAr has a positive density characteristic because of diffusion layers 4 and 5 with high surface impurity density, and boron as an impurity has a positive temperature characteristic, so R and (r) in the equation are adjusted to obtain the output voltage after the temperature characteristic is adjusted.