Properties of Intrinsic a-Si Films Deposited From Higher Order Silanes by Chemical Vapor Deposition

Abstract

AbstractAmorphous silicon films have been deposited by chemical vapor deposition using disilane at temperatures between 360 and 525°C at growth rates up to 50 A/s. Intrinsic films have the following properties: σp less than 5 × 10−6 (Ω-cm)−l; σd less than 5 × 10−11 (Ω-cm)−1 with Ea = 0.7 to 0.8 eV; diffusion length around 0.1 μm; Urbach energy 48 to 55 meV; and mid-gap density of states greater than 5 × 1016 cm−3 eV−1. Boron compensation improved collection efficiency by lowering the mid-gap density of states, not by improving the μτ product. Pin cells with effíciencies of 4% and Jsc = 10.9 mA/cm2 (87.5 mW ELH) were fabricated.