On Gas-Phase Depletion During LPCVD of GeSi films using GeH_4/SiH_4 and GeH_4/Si_2H_6 Gas Sources

摘要

In this work, a comparative study of Low Pressure Chemical Vapour Deposition (LPCVD) of Germanium-Silicon films has been carried out for two different precursor systems. Namely, mixtures of pure GeH_4 and SiH_4, of GeH_4 and Si_2H_6 were used. The experiments were performed using a long 60-cm wafer boat fully loaded with 3-inch wafers with a 0.5-cm spacing in between. For both systems, the distribution of deposition rate, germanium content and crystallinity of the films along the gas-flow direction in a batch-type reactor were compared. The effects of the gas-phase depletion on properties of the layers deposited at a temperature of 430 °C were studied.