Polycrystalline silicon thin films on glass for photovoltaic applications

N. BUDINI; J. A. SCHMIDT; F. M. OCHOA; P. A. RINALDI; R. D. ARCE; R. H. BUITRAGO

Advances in Materials Science Research

NOVA PUBLISHERS INC.

Lugar: New York; Año: 2011; p. 1 - 15

In this chapter, we briefly present the state of the art in some deposition and processing techniques that can be used to obtain thin polycrystalline silicon (poly-Si) films on glass substrates. In particular, we focus on the ultimate advances to date related to the technique of metal induced crystallization of amorphous silicon, which allows to produce large crystalline grains (sizes over 100 μm) at low temperatures (lower than 600 ºC) by means of thermally activated solid phase transformations. Specifically, we discuss in more detail the use of nickel as the metallic inductor of silicon crystallization, and its influence on grain nucleation and growth. We also analyze the relevant concept of the solid phase epitaxial crystallization of an amorphous silicon thin film, deposited onto a previously crystallized seed layer, to produce poly-Si. The effects of doping on crystallization are presented, together with the problems that it entails. Taking account of all the issues presented, we propose a suitable process, scalable to industrial levels, which will allow to produce a competitive large-grained poly-Si solar cell with high efficiency and at low costs.