Thickness evolution of the microstructure of si:h films in the amorphous-to-microcrystalline phase transition region
Proceedings of the 3rd World Conference on Photovoltaic Energy Conversion
Real time spectroscopic ellipsometry (RTSE) has been applied to develop deposition phase diagrams that describe the thickness evolution of the phase of hydrogenated silicon (Si:H) thin films. Such diagrams can be applied to establish optimization principles for the intrinsic (i-) layers incorporated into high performance solar cells based on amorphous Si:H (a-Si:H). The phase diagrams for the growth of Si:H on a-Si:H film substrates incorporate two transitions versus accumulated thickness, the first from the amorphous to the mixed-phase (amorphous + microcrystalline) growth regime [the a→(a+μc) transition] and the second from the mixed-phase to single-phase microcrystalline growth regime [the (a+μc)→μc transition]. Methods have been developed to extract the evolution of the volume fraction of microcrystalline Si:H (μc-Si:H) within the mixed-phase growth regime. Similar deposition phase diagrams have also been developed to optimize p-type Si:H layers for a-Si:H-based n-i-p and p-i-n cells.