Suppression of crystalline growth in silicon films deposited from hydrogen diluted silane using a layer-by-layer approach

Si:H films with a thickness of approximately 450 nm have been deposited with rf-PECVD using a plasma of silane diluted with hydrogen. The aim was to grow heterogeneous films without an amorphous to microcrystalline phase transition. A layer-by-layer scheme was applied in which thin interlayers deposited from pure silane are included with the intention to interrupt the crystalline growth that is characteristic to the deposition with hydrogen dilution of silane. Raman spectroscopy and TEM imaging have confirmed that the application of the amorphous interlayers results in a decrease of the crystalline fraction of the layer-by-layer films compared to films grown with continuous hydrogen dilution. Absorption coefficient spectra of the films before and after light soaking have been investigated.