Hydrogenated microcrystalline silicon thin film growth in the DC saddle field PECVD system

Hydrogenated amorphous silicon (a-Si:H) and microcrystalline silicon (muc-Si:H) thin films were grown at the threshold of the amorphous-to-microcrystalline phase transition in a modified direct current (DC) saddle field plasma enhanced chemical vapour deposition (SF-PECVD) system. For the first time, the microcrystalline content of the resulting films was successfully controlled through direct manipulation of the substrate surface bias during growth. This effect was quantified for multiple pressures.; The as-grown microcrystalline content and the laser-induced crystallization of the films was quantified using Raman scattering spectroscopy. The optoelectronic and morphological properties of the films were measured. These measurements included UV-Vis and IR spectroscopy, temperature-dependent four-point conductivity, photoluminescence, atomic force microscopy, and spectroscopic ellipsometry. All measurements correlated well with the microcrystalline content of the films.; The growth of muc-Si:H in an ion-bombarding environment was modeled using a general formalism applicable to all methods of muc-Si:H growth. The simulation results of the model showed good qualitative agreement to experimental findings from this work as well as the literature.; The operation of the SF-PECVD system using a large-area externally applied substrate bias was examined under varying conditions and new limitations to the large area application of substrate bias were discovered. Three previously unidentified plasma operation regimes were identified that explain the role of substrate bias in controlling microcrystalline growth. A methodology for the design of SF-PECVD systems for the growth of muc-Si:H was described.