Correlations between stress and microstructure into LPCVD silicon films

Silicon films have been deposited by low pressure chemical vapour depositio n (LPCVD) from silane SiH4 at temperatures and pressures varying respective ly from 520 degrees C to 750 degrees C and from 100 mTorr to 300 mTorr. Fil ms residual stresses are studied as a function of deposition parameters (te mperature and total pressure). Major stress variations (from compressive to tensile values) are explained through the cumulated influences of the depo sition and crystallisation phenomena, evidencing correlations with silicon microstructure (amorphous, semicrystalline, mixed crystalline or polycrysta lline) characterised by transmission electron microscopy (TEM). Finally, re sidual stress and silicon microstructure are directly related to the ratio between deposition and crystallisation rates, enabling the development of l aws for their modelling into silicon films deposited by LPCVD.