Abstract: The invention provides an improved BiCMOS device and a method of fabricating such a BiCMOS device which requires fewer process steps than known fabrication methods. In one embodiment, the invention provides a method of forming an interpoly capacitor in a BiCMOS device which maintains the thickness of the interpoly dielectric in the capacitor while a window is etched for the emitter in a bipolar transistor. The method includes the use of a thin polysilicon layer overlying the oxide layer, which protects the oxide from etching while the emitter window is etched.

Abstract: A gate array is provided in which active areas within the substrate are arranged in alternating columns of opposite conductivity type and symmetrical about the center lines through each column so that CMOS devices can be advantageously formed by allocating only small increments of active area to metal routing. The substrate and well taps are also symmetrical about the column center line. The active area symmetry allows p-channel and n-channel transistors to be combined where the p-channel transistor is on either the right or left, thus increasing the flexibility in placing the elements within the integrated circuit chip.