Hot-wire chemical vapor deposition (HWCVD) has been shown to be promising for depositing thin film silicon materials at higher deposition rate than conventional plasma-enhanced CVD. Due to the higher atomic H density in the gas phase, it is not straightforward to utilize the full benefit of the higher deposition rate of the HWCVD in thin film solar cells in the p-i-n configuration on textured SnO2:F (superstrate configuration). The Transparent Conducting Oxide (TCO) is found to be very sensitive for high atomic hydrogen ambient. This paper presents our investigations on the implementation of ultrathin ZnO:Al protection layers, allowing higher temperatures during i-layer deposition, and thus, higher deposition rates. (c) 2005 Elsevier B.V. All rights reserved.