Silicon deposition on mullite ceramic substrates for thin‐film solar cells

Abstract

Fabrication of silicon thin film (TF-Si) solar cells with high throughput on cheap substrates requires both adequate deposition technique and suitable substrate. Our approach consists of depositing polycrystalline silicon films with thickness of 10–30 μm by Rapid Thermal Chemical Vapour Deposition (RT-CVD) onto newly developed mullite ceramics. Compared to alumina, the latter has the advantage that the thermal expansion coefficient can be matched to that of silicon by compositional adjustment. The substrates are elaborated by the tape casting process, enabling continuous production on large size (≥50 cm width). The polycrystalline silicon thin film with structure p+/p is deposited at atmospheric pressure by RT-CVD, tailoring in-situ the temperature and doping profiles. High deposition rates of 1–5 μm/min are commonly obtained in the temperature range 1000–1200°C. In the present paper, the overall optical, crystalline and electrical features of TF-Si on mullite ceramics are presented. Copyright © 1999 John Wiley & Sons, Ltd.