Lifetime degradation in multicrystalline silicon under illumination at elevated temperature: Indications for the involvement of hydrogen

• Main Authors: Bredemeier, Dennis, Walter, Dominic C., Schmidt, Jan
• Format: Conference Proceeding
• Language: English
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.5049320

We examine the lifetime degradation in multicrystalline silicon (mc-Si) under illumination at elevated temperature, an effect frequently denoted as ‘LeTID’ (‘Light and elevated Temperature Induced Degradation’). Our lifetime analysis of belt-furnace-fired high-performance mc-Si wafers shows that LeTID is most pronounced on samples with Al2O3/SiNx−stack passivation. In contrast to that, the degradation on samples coated with Al2O3 single-layers is very small. We identify the presence of SiNx to be a key component to trigger the defect activation process. Our measurements suggest that hydrogen released during the high-temperature firing from the hydrogen-rich PECVD-deposited SiNx into the silicon bulk plays a major role in the defect activation process. Additionally, we find that the magnitude of lifetime degradation increases exponentially with increasing peak temperature during fast-firing. Comparing these results with recently published results from the literature, we conclude that hydrogen-metal complexes are possible candidates for the root cause of LeTID.