Author:

Keywords:

Science & Technology, Technology, Physical Sciences, Energy & Fuels, Materials Science, Multidisciplinary, Physics, Applied, Materials Science, Physics, Hydrogenated amorphous silicon (a-Si:H), hydrogen (H-2) plasma, passivation, silicon heterojunction (SHJ) solar cells, DENSITY-OF-STATES, SURFACE PASSIVATION, AMORPHOUS-SILICON, ION-BOMBARDMENT, DEEP LEVELS, GAP STATES, INTERFACE, IDENTIFICATION, SPECTROSCOPY, CENTERS, ELECTRON-SPIN-RESONANCE, CRYSTALLINE SILICON, ECR PLASMA, 0206 Quantum Physics, 0906 Electrical and Electronic Engineering, 0912 Materials Engineering, 4009 Electronics, sensors and digital hardware, 4016 Materials engineering

Abstract:

© 2018 IEEE. A fully dry and hydrofluoric-free low-temperature process has been developed to passivate n-type crystalline silicon (c-Si) surfaces. Particularly, the use of a hydrogen (H2) plasma treatment followed by in situ intrinsic hydrogenated amorphous silicon (a-Si:H) deposition has been investigated. The impact of H2 gas flow rate and H2 plasma processing time on the a-Si:H/c-Si interface passivation quality is studied. Optimal H2 plasma processing conditions result in the best effective minority carrier lifetime of up to 2.5 ms at an injection level of 1 × 1015 cm-3, equivalent to the best effective surface recombination velocity of 4 cm/s. The reasons that enable such superior passivation quality are discussed in this paper based on the characterization of the a-Si:H/c-Si interface and c-Si substrate using transmission electron microscopy, high angle annular dark field scanning transmission electron microscopy, and deep-level transient spectroscopy.