Deposited multilayer passivation - for silicon devices

摘要

Passivating oxides comprising at least two layers, one of pure SiO2 the other of phosphorus doped SiO2 are deposited on semiconductor devices. A third layer of pure SiO2 may be added to protect the P-doped layer from humidity etc. The first SiO2 layer may also form the dielectric in MOS capacitors and transistors. The SiO2 layers are deposited from SiH4/O2 at 350-450 degrees C, P2O5/SiO2 from SiH4/PH3/O2 at 320-360 degrees C or from an alkoxysilane plus trimethylphosphine. Deposition is followed by heat treatment at 750-850 degrees C to density the oxide and reduce surface state density.