Evolution of Microstructure and Phase in Amorphous, Protocrystalline, and Microcrystalline Silicon Studied by Real Time Spectroscopic EllipsometrySolar Energy Materials and Solar Cells (2003)
Real time spectroscopic ellipsometry has been applied to develop deposition phase diagrams that can guide the fabrication of hydrogenated silicon (Si:H) thin ﬁlms at low temperatures (<300°C) for highest performance electronic devices such as solar cells. The simplest phase diagrams incorporate a single transition from the amorphous growth regime to the mixed-phase (amorphous+microcrystalline) growth regime versus accumulated ﬁlm thickness [the a ͢(a+µc) transition]. These phase diagrams have shown that optimization of amorphous silicon (a-Si:H) intrinsic layers by RF plasma-enhanced chemical vapor deposition (PECVD) at low rates is achieved using the maximum possible ﬂow ratio of H₂ to SiH₄ that can be sustained while avoiding the a͢(a+µc) transition. More recent studies have suggested that a similar strategy is appropriate for optimization of p-type Si:H thin ﬁlms. The simple phase diagrams can be extended to include in addition the thickness at which a roughening transition is detected in the amorphous ﬁlm growth regime. It is proposed that optimization of a-Si:H in higher rate RF PECVD processes further requires the maximum possible thickness onset for this roughening transition.
- Spectroscopic ellipsometry; Hydrogenated silicon; Thin ﬁlms
Publication DateJanuary 30, 2003
Citation InformationR. W. Collins, A. S. Ferlauto, G. M. Ferreira, Chi Chen, et al.. "Evolution of Microstructure and Phase in Amorphous, Protocrystalline, and Microcrystalline Silicon Studied by Real Time Spectroscopic Ellipsometry" Solar Energy Materials and Solar Cells Vol. 78 (2003)
Available at: http://works.bepress.com/jmpearce/72/