The coming of age of a new PV wafer technology-some aspects of EFG polycrystalline silicon sheet manufacture

Abstract

We trace the pioneering research and development experiences over the past 25 years which have led to a full scale manufacturing line for photovoltaic modules utilizing polycrystalline silicon wafers produced by the Edge-defined Film-fed Growth (EFG) technique. We examine the progress made in two core areas in detail -crystal growth productivity and wafer bulk quality -which have justified the recent scale up of EFG technology at ASE Americas to the multi-megawatt level. We identify areas in which future advances will enable a crystalline silicon-based EFG technology to compete with cost targets anticipated for the photovoltaics marketplace beyond the year 2000.

Manufacturing technology for ribbon silicon (EFG) wafers and solar cells

“…The unique properties of the EFG wafer have motivated development of special solar cell manufacturing techniques at ASE, which are designed to compensate for low as-grown wafer bulk lifetimes and are very effective in optimally upgrading EFG wafer bulk electronic quality. [2][3][4][5] These are discussed in the next section.…”

Status, Trends, Challenges and the Bright Future of Solar Electricity from Photovoltaics

“…An interesting option in Si solar cell manufacturing is the growth of ribbons [62,63]. Ribbons do not require the expensive sawing process.…”