Micro-Raman stress characterization of polycrystalline silicon films grown at high temperature

In this paper the residual stress of polycrystalline silicon (poly-Si) grown at high temperature in a vertical LPCVD reactor has been studied using micro-Raman spectroscopy. The samples were prepared on Si(1 0 0) n-type substrates coated with 100 nm of SiO2. The films were deposited in the temperature range of 750–900 °C at pressures of 5 and 10 Torr. The as-deposited poly-Si films are highly crystalline and show tensile stress. Micro-Raman measurements show that the residual stress is reduced as the deposition temperature is increased and, above 800 °C, tensile stress is reduced to less than 150 MPa. These results indicate that high quality, high crystalline and low strained poly-Si films can be obtained in this type of reactor using higher deposition temperature.