Sontheimer, T.; Becker, C.; Gall, S.; Rech B.: Crystal nucleation in electron-beam evaporated amorphous silicon on ZnO:Al- and SiN-coated glass for thin film solar cells. Physica Status Solidi C 7 (2010), p. 525-528
The crystallization of high-rate electron beam evaporated amorphous silicon on ZnO:Al-coated glass and SiN-coated glass was investigated by applying ex-situ optical microscopy and isothermal annealing. The nucleation process in solar cell structures consisting of n+-Si(PECVD)/p-Si/p+-Si layers was analyzed and subsequently compared to the phase transition in p-Si and n+-Si(PECVD)/p-Si on SiN and ZnO:Al-coated glass. With a high steady-state nucleation rate and a low activation energy (EIss = 2.7 eV), the nucleation process of Si on ZnO:Al has shown to differ significantly from nucleation on SiN (EIss= 4.5 eV) in the investigated temperature regime of 560 °C to 600 °C. The experiments revealed that the n+-Si(PECVD) layer did not serve as a nucleation layer and did not influence the nucleation of p-Si on SiN. On ZnO:Al, however, the nucleation rate of n+-Si(PECVD)/p-Si was found to be smaller than the nucleation rate of a single p-Si layer. While the p+-Si promotes the nucleation on SiN, it did not affect the nucleation process of Si on ZnO:Al.