Effects of Ultrasonic Cleaning on Carrier Lifetimes and Photovoltage in Monocrystalline Silicon

Author(s)

A. Nadtochiy, Oleg Korotchenkov, Markus Drapalik, Viktor Schlosser

Abstract

Effects of a kHz-frequency ultrasonic cleaning of silicon wafers on free carrier lifetimes and the photovoltage magnitude are addressed. It is found that the initial photovoltage decay, taken before ultrasonic treatments, can be fitted to a double-exponent form, exhibiting the involvement of shorter- and longer time recombination and trapping centers. The decay speeds up remarkably due to the treatment, and the rapid component of the decay grows at the expense of the slow component. It is also found that, before the treatment, the decay time is markedly non-uniform over the wafer surface, implying the existence of distributed sites affecting carrier lifetimes. The cleaning causes an overall smoothening of the lifetime distribution, which is accompanied by the above shortening. A likely explanation of the effects is based on two facts: (i) the cavitating bubbles are capable of locally removing the surface oxide layer affecting the dangling bonds on the bare Si surface, and (ii) the oxygen and hydrogen, decomposed in water at elevated pressures and temperatures occurring inside a cavitating bubble, can micro-precipitate the Si wafer thus affecting the recombination rate.

Organisation(s)

Electronic Properties of Materials

External organisation(s)

Taras Shevchenko National University of Kyiv (KNU)

Journal

Solid State Phenomena (Diffusion and defect data B)

Volume

178-179

Pages

221-225

No. of pages

5

ISSN

1012-0394

DOI

https://doi.org/10.4028/www.scientific.net/SSP.178-179.221

Publication date

2011

Peer reviewed

Yes

Austrian Fields of Science 2012

103009 Solid state physics, 103018 Materials physics

Portal url

https://ucris.univie.ac.at/portal/en/publications/effects-of-ultrasonic-cleaning-on-carrier-lifetimes-and-photovoltage-in-monocrystalline-silicon(bee14784-4a0f-49c6-b076-f7af4748e8a6).html