Method for making a bipolar transistor and capacitors using doped polycrystalline silicon or metal silicide

摘要

The invention provides a method for making a semiconductor device including a bipolar transistor and a capacitor. An oxide film and a silicon nitride film are formed and patterned on a semiconductor substrate. A layer of polycrystalline silicon or of metal silicide containing an impurity is formed between an emitter electrode and an emitter region of the transistor and between an electrode and a thin oxide film of the capacitor. The doped polycrystalline silicon or metal silicide is then patterned to form a barrier layer protecting the oxide film and an intermediate layer acting as a diffusion source to the underlying substrate.