Continuous-mode fabrication of amorphous silicon solar cells on polyimide substrates

Abstract

Research results obtained from single-chamber deposition systems have guided the development and optimization of a continuous process for producing flexible amorphous hydrogenated silicon (a-Si:H) solar cells on polyimide substrates. Devices are constructed from polyimide film 2 × 10 −3 in thick metallized with a bilayer 1000 Å thick consisting of Al/TiN for a bottom contact and p +-i-n + layers 200, 5000 and 100 Å thick of a-Si:H with a quarter-wavelength indium tin oxide layer as a top contact. This system currently produces devices of 6.2% efficiency. The multichamber system consists of four reactors within one large chamber. A substrate outgassing chamber is followed sequentially by p +-i-n + glow discharge chambers. Special design features reduce cross-contamination to less than 1 ppm at operating pressures of 1 Torr. Concerns relating to continuous processing and plastic substrates are discussed.