Input transient protection for complementary insulated gate field effect transistor integrated circuit device

Claim 1

In a semiconductor device of the type which has a body of semiconductive material of one type and degree of conductivity and which further has a plurality of diffused regions in said body adjacent to a surface thereof for defining active and passive circuit elements including a pair of insulated gate field effect transistors, one of which has spaced source and drain regions in said body adjacent to said surface and the other having a diffused well region of conductivity type opposite to that of said body in said body adjacent to said surface and a pair of source and drain regions of said one type conductivity within said well region, resistor and diode elements characterized by relatively high resistance and relatively low diode breakdown strength, respectively, comprising: a diffused resistor region, of said opposite type conductivity and having the same depth and impurity concentration gradient as said diffused well region, in said body adjacent to said surface and defining a gradual PN junction in said body, whereby the breakdown strength of said PN junction is relatively high, said juNction having a boundary which intercepts said surface, at least one diffused diode region, of said opposite type conductivity, in said body adjacent to said surface in overlapping relation to a portion of said boundary of said gradual PN junction and itself defining an abrupt PN junction of relatively low breakdown strength with the material of said body, and spaced conductors coupled to said resistor region for connecting said resistor to other elements of said device.