ULTRA-LOW PRESSURE CHEMICAL VAPOR-DEPOSITION OF POLYCRYSTALLINE AND AMORPHOUS-SILICON

The deposition of undoped polycrystalline and amorphous silicon in an ultra-low pressure chemical vapour deposition system capable of achieving operating pressure of 0.03 Pa is discussed. It is found that at deposition temperatures in the region of 630-degrees-C and reactor pressures of less than 1.3 Pa very large grained polycrystalline silicon films are obtained, and in this regime the growth rate is independent of the reactor pressure. Excellent uniformity is obtained and the process can be easily scaled up for large substrates and high volume batch production.