LAUSR

Abstract We study the effect of plasma-enhanced chemical vapor deposition (PECVD) SiNx process to atomic layer deposited (ALD) Al2O3 films on crystalline silicon surface passivation. The plasma-induced damage on Al2O3 films is affected by the methods of PECVD process (direct or microwave), and the states (as-deposited or annealed) and the thickness of ALD-Al2O3 films. The passivation degradation may be related to the doping of Si, N and H atoms into Al2O3 films during PECVD process, and is mainly manifested in the form of affecting interface defect density rather than negative fixed charge density. In particular, the annealed thick Al2O3 films with direct-PECVD SiNx process show more severe passivation degradation. Anyhow, to the great degree, the passivation quality can be repaired and further improved by post-annealing. Low temperature long time annealing can effectively increase the lifetime of the ALD-Al2O3/PECVD-SiNx stacks, while it cannot be simply replaced by a rapid high temperature firing. By post-annealing repairing, an absolute 0.13% increase in efficiency can be achieved for p-PERC solar cells.