Solid Phase Epitaxy on large grained Polycrystalline seed layers

R.H. BUITRAGO; J. A. SCHMIDT; N. BUDINI; G. RISSO; P. RINALDI; A.G. BENVENUTO; R. D. ARCE

Hamburgo

Conferencia; 24th European Photovoltaic Energy Conference; 2009

The epitaxial thickening of a polycrystalline silicon seed layer grown on a glass substrate is of great interest for the preparation of polycrystalline silicon thin film solar cells and other thin film devices. In this paper, we work on the solid phase epitaxial growth of lightly boron-doped (p-) silicon at temperatures below 580 ºC on polycrystalline seed layers. Considering the design of a solar cell, we deposited seed layers with a boron concentration profile similar to the one used to obtain a back surface field. The structures were glass/p+/p-/Ni, with thicknesses of 40 nm for the p+ layer and 160 nm for the p- layer. In this case, the seed layer gives grain sizes over 50 microns – compared to the 150 microns obtained without the p+ layer – thus indicating a negative influence of the high boron concentrations.