Title :
Hydrogen in silicon: current understanding of diffusion and passivation mechanisms
Author :
Sopori, B.L. ; Deng, X. ; Benner, J.P. ; Rohatgi, A. ; Sana, P. ; Estreicher, S.K. ; Park, Y.K. ; Roberson, M.A.
Author_Institution :
Nat. Renewable Energy Lab., Golden, CO, USA
Abstract :
A model for H diffusion and passivation is described that explains the experimental results from solar cell passivation, such as variations in the degree of passivation in substrates from different vendors, passivation due to forming gas anneals following Al alloying, and the effects of plasma enhanced chemical vapor deposition (PECVD) nitridation. Two major features of the model are inclusion of: (i) a new H diffusion mechanism involving hydrogen-vacancy complex {V-H} formation; and (ii) surface damage that causes high solubility of H at the Si surface and dissociation of molecular H at low temperatures. The theoretical analysis, based on static potential energy surfaces at the ab-initio Hartree-Fock level, identifies some details of diffusion mechanisms
Keywords :
annealing; diffusion; hydrogen; passivation; plasma CVD; plasma CVD coatings; semiconductor device models; semiconductor device testing; semiconductor doping; semiconductor growth; semiconductor thin films; silicon; solar cells; Al alloying; H diffusion model; PECVD; Si:H; ab-initio Hartree-Fock level; dissociation; gas anneals; hydrogen-vacancy complex formation; low temperatures; nitridation; plasma enhanced chemical vapor deposition; solar cell passivation; static potential energy surfaces; substrates; surface damage; Alloying; Annealing; Chemical vapor deposition; Hydrogen; Passivation; Photovoltaic cells; Plasma chemistry; Plasma temperature; Potential energy; Silicon;
Conference_Titel :
Photovoltaic Energy Conversion, 1994., Conference Record of the Twenty Fourth. IEEE Photovoltaic Specialists Conference - 1994, 1994 IEEE First World Conference on
Conference_Location :
Waikoloa, HI
Print_ISBN :
0-7803-1460-3
DOI :
10.1109/WCPEC.1994.520526
