Hydrogenated Amorphous Silicon Carbide Prepared using DC Saddle Field PECVD for Photovoltaic Applications

Hydrogenated amorphous silicon carbide (a-SiC:H) can provide exceptional surface passivation essential for high-efficiency crystalline silicon solar cells. This thesis reports on the fundamental study of a-SiC:H films deposited using a novel deposition technique, DC saddle field PECVD, in contrast to the conventional industrial use of RF-PECVD. The growth conditions were optimized and correlated with passivating, structural, and optical characteristics. The lifetime has a strong dependency on deposition temperature and improves by over two orders of magnitude as the temperature increases; the maximum lifetime achieved in this work reached 0.5 ms. In addition, the Tauc optical gap can be increased from 1.7 eV to 2.3 eV by varying the precursor gas mixture ratio. Post-deposition annealing experiments demonstrate thermal stability of the samples deposited at 250 °C and in some instances shows improvement in passivation quality by a factor of two with a one-step annealing treatment at 300 °C for 15 minutes.MAS