Low-temperature deposition of weakly-stressed nanocrystalline silicon films by reactive magnetron sputtering

We discuss the fabrication and characterization of undoped hydrogenated and crystallized silicon thin films grown by reactive magnetron sputtering at growth rate of about 2 Å/s and at a temperature as low as 100 °C for various ratios of hydrogen dilution in the gas phase mixture (argon + x% hydrogen). Combined infrared absorption and Raman scattering spectroscopy techniques as well as conventional and high resolution transmission electron microscopy and stress measurements are used to fully characterize the films. In this temperature range, a minimum hydrogen dilution of 30% with respect to the plasma mixture (argon + hydrogen) is necessary to produce nanocrystalline films with crystalline volume fraction of about 65%. Moreover, these films are found to promote much lower stress intensity than those reported in previous works. The nature and strength of the stresses are dependent on the film microstructure.