Investigation of isochronal annealing on the optical properties of HWCVD amorphous silicon nitride deposited at low temperatures and low gas flow rates

6th International Conference on Optical, Optoelectronic and Photonic Materials and Applications 2014

Muller, T.F.G.^1 ; Jacobs, S.^1 ; Cummings, F.R.^1 ; Oliphant, C.J.^2 ; Malgas, G.F.^1 ; Arendse, C.J.^1

Department of Physics, University of the Western Cape, Private Bag X17, Bellville

7535, South Africa^1

National Metrology Institute of South Africa, Private Bag X34, Lynwood Ridge, Pretoria

0040, South Africa^2

关键词: Bruggeman effective medium approximation;    Chemical vapour deposition;    Deposition regimes;    Filament temperature;    Isochronal annealing;    Low gas flow rates;    Reflection spectra;    Structural complexity;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/619/1/012014/pdf
DOI  :  10.1088/1742-6596/619/1/012014

来源: IOP

【 摘 要 】

Hydrogenated amorphous silicon nitride (a-SiNx:H) is used as anti-reflection coatings in commercial solar cells. A final firing step in the production of micro-crystalline silicon solar cells allows hydrogen effusion from the a-SiNx:H into the solar cell, and contributes to bulk passivation of the grain boundaries. In this study a-SiNx:H deposited in a hot-wire chemical vapour deposition (HWCVD) chamber with reduced gas flow rates and filament temperature compared to traditional deposition regimes, were annealed isochronally. The UV-visible reflection spectra of the annealed material were subjected to the Bruggeman Effective Medium Approximation (BEMA) treatment, in which a theoretical amorphous semiconductor was combined with particle inclusions due to the structural complexities of the material. The extraction of the optical functions and ensuing Wemple-DeDomenici analysis of the wavelength-dependent refractive index allowed for the correlation of the macroscopic optical properties with the changes in the local atomic bonding configuration, involving silicon, nitrogen and hydrogen.