Hydrogen-induced degradation: Explaining the mechanism behind light- and elevated temperature-induced degradation in n- and p-type silicon

• Published in: Solar energy materials and solar cells Vol. 207; p. 110353
• Main Authors: Chen, Daniel, Hamer, Phillip, Kim, Moonyong, Chan, Catherine, Ciesla nee Wenham, Alison, Rougieux, Fiacre, Zhang, Yuchao, Abbott, Malcolm, Hallam, Brett
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2020; Elsevier BV
• Subjects: Activation energy; Degradation; Diffusion layers; Emitter diffusion; Experimentation; High temperature; Hydrogen; Hydrogen storage; Hydrogen-induced degradation; Illumination; LeTID; n-type silicon; p-type silicon; Recovery; Silicon; Silicon wafers; Surface-related degradation; Wafers; Surface-related degradation; Hydrogen; n-type silicon; Emitter diffusion; Hydrogen-induced degradation; LeTID; p-type silicon
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2019.110353

Light- and elevated temperature-induced degradation (LeTID) has been extensively studied on p-type silicon materials with increasing evidence suggesting the involvement of hydrogen. Recent findings of the identical phenomenon in n-type silicon wafers have further opened up new areas of understanding into the inherent behavior and root cause of the defect. In this work, we compare LeTID observed in both p- and n-type silicon wafers under both dark and illuminated annealing conditions, highlighting previously unobserved similarities in defect formation and recovery kinetics. We report thermal activation energies of the LeTID-related degradation and recovery in n-type silicon to be 0.76 ± 0.02 eV and 0.97 ± 0.01 eV without illumination, respectively, and 0.70 ± 0.05 eV and 0.83 ± 0.15 eV under illumination (0.02 kWm−2), respectively. Furthermore, we present additional experimentation demonstrating the thermal and illumination dependency of surface-related degradation (SRD) in n-type silicon. We report an extracted activation energy of this SRD of 0.38 ± 0.10 eV. Through modelling of the hydrogen charge state fractions, we speculate that the behavior of LeTID both in the dark and under illumination may be explained by the migration of and interactions between charged hydrogen species and dopant atoms within the diffused layers and the silicon bulk. •Identical LeTID behaviours can be induced in vastly different n- and p-type Si wafers.•Surface diffused layers can modulate LeTID degradation and recovery kinetics.•Hydrogen modelling can explain LeTID acceleration and retardation under light.•The onset of SRD is dependent on near-surface electric fields and local Fermi levels.