Efficient passivation of n-type and p-type silicon surface defects by hydrogen sulfide gas reaction

An efficient surface defect passivation is observed by reacting clean Si in a dilute hydrogen sulfide–argon gas mixture (<5% H2S in Ar) for both n-type and p-type Si wafers with planar and textured surfaces. Surface recombination velocities of 1.5 and 8 cm s−1 are achieved on n-type and p-type Si wafers, respectively, at an optimum reaction temperature of 550 °C that are comparable to the best surface passivation quality used in high efficiency Si solar cells. Surface chemical analysis using x-ray photoelectron spectroscopy shows that sulfur is primarily bonded in a sulfide environment, and synchrotron-based soft x-ray emission spectroscopy of the adsorbed sulfur atoms suggests the formation of S–Si bonds. The sulfur surface passivation layer is unstable in air, attributed to surface oxide formation and a simultaneous decrease of sulfide bonds. However, the passivation can be stabilized by a low-temperature (300 °C) deposited amorphous silicon nitride (a-Si:NX:H) capping layer.

Description

This is an author-created, un-copyedited version of an article accepted for publication/published in Journal of Physics: Condensed Matter. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1361-648X/ac1ec8. This article will be embargoed until 09/03/2022.

Keywords

silicon, surface passivation, hydrogen sulfide reaction, photoelectron spectroscopy

Citation

Das, U K, R Theisen, A Hua, A Upadhyaya, I Lam, T K Mouri, N Jiang, et al. “Efficient Passivation of N-Type and p-Type Silicon Surface Defects by Hydrogen Sulfide Gas Reaction.” Journal of Physics: Condensed Matter 33, no. 46 (September 3, 2021): 464002. https://doi.org/10.1088/1361-648X/ac1ec8.