The Development of High-Rate Deposition Technology for Microcrystalline Silicon for High-Efficiency a-Si/μc-Si Tandem Solar Module

A localized plasma confinement chemical vapor deposition (LPC-CVD) method with special cathode structures was proposed to solve problems of stability and uniformity of plasma under high pressure (>;1000 Pa). The initial conversion efficiency achieved by LPC-CVD for an a-Si/μc-Si tandem solar cell was 10.4% (1 cm²) for a 550 × 650 mm² substrate at the deposition rate of 2.2 nm/s. Since then, we have been developing high-rate deposition technology for 1100 × 1400 mm² substrates (Generation 5.5 (G5.5) size). A-Si/ μc-Si tandem solar modules have been achieved with an efficiency of 11.1% (initial) and 10.0% (stable) and a deposition rate of 2.4 nm/s on a G5.5-size substrate.