Novel silicon surface passivation by porous silicon combined with an ultrathin Al^sub 2^O3 film

• Published in: Journal of materials science. Materials in electronics Vol. 24; no. 12; p. 5035
• Main Authors: Salem, M, Ben Rabha, M, Bessais, B, Elkhakani, M A, Gaidi, M
• Format: Journal Article
• Language: English
• Published: New York Springer Nature B.V 01-12-2013
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-013-1518-2

We report on a dual passivation approach of monocrystalline-silicon (c-Si), which combines porous silicon (PS) treatment and pulsed laser deposition (PLD) of Al^sub 2^O3 ultrathin layer. Al^sub 2^O3 ultrathin films were deposited, under an oxygen background pressure of 10 mTorr. In this work we demonstrate that the dual treatment Al^sub 2^O3/PS provide excellent passivation quality of c-Si surfaces. Surface passivation and reflectivity properties are investigated before and after heat treatment at 700 °C. The level of surface passivation is quantified using photoconductance and Fourier-transform infra-red absorption techniques. X-ray diffraction analysis suggested that the heat treatment leads to an average crystallite size decrease which help the diffusion of the Al^sub 2^O3 NPs along the wafer surface. As a result, the effective minority carrier lifetime increases from 2 to 7 [mu]s. Our results demonstrate that this dual treatment not only provides strong passivation of the c-Si substrate but decreases also the total surface reflectivity at 500 nm (from 28 % for untreated c-Si samples to 7 % for Al^sub 2^O3/PS treated ones).[PUBLICATION ABSTRACT]