Method for fabricating BiCMOS device

摘要

A method for fabricating a bipolar complementary metal oxide semiconductor device, includes a first step of forming a three-layered substrate of p-/n+/n- type or n-/p+/p- type and forming p- and n-wells to be adjacent to each other to the bottom of the top layer of the three-layered substrate; a second step of isolating the p- and n-wells from each other and defining a region for a bipolar transistor on one side to separate base/emitter regions from each other; a third step of defining a gate region to form a metal- oxide semiconductor transistor in each of the p- and n-wells and forming collector/emitter regions in the bipolar transistor region; and a fourth step of forming an n-type metal oxide semiconductor transistor, a p-type metal oxide semiconductor transistor and a bipolar transistor on the p-well, n-well and collector/emitter regions, respectively, and forming source/drain and base electrodes through diffusion by using a doped polycrystalline silicon sidewall spacer.