Thickness evolution of the microstructure of Si:H films in the amorphous-to-microcrystalline phase transition region

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/spl rarr/(a+/spl mu/c) transition] and the second from the mixed-phase to single-phase micro-crystalline growth regime [the (a+/spl mu/c)/spl rarr//spl mu/c transition]. Methods have been developed to extract the evolution of the volume fraction of microcrystalline Si:H (/spl mu/c-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.