Kumar, Sanjai and Singh , P. K. and Chilana, G. S. and Dhariwal, S. R. (2009) Generation and recombination lifetime measurement in silicon wafers using impedance spectroscopy. Semiconductor Science and Technology, 24 (9). 095001-1-095001-8. ISSN 0268-1242

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Abstract

Minority carrier lifetime in silicon wafers has been measured by applying an impedance spectroscopy technique (IST). Induced p+–p and p–n junctions were formed on both sides of the silicon wafer by thermally evaporating semitransparent metal layers of palladium and aluminium respectively. As such, no thermal treatment was given to the device, and therefore there is no diffusion of impurities inside the semiconductor and the two junctions are induced in the form of accumulation and depletion regions of charge carriers respectively. Both generation and recombination lifetimes applicable under the reverse and forward bias conditions respectively have been measured. The generation lifetime was estimated to be around 73 µs, whereas the recombination lifetime has been found to be about 11 µs. It is shown that the effective recombination lifetime is determined mainly by surface recombination velocity at the silicon–palladium interface. The effective minority carrier lifetime as measured by the microwave-detected photoconductive decay method on the same sample is 12 µs which is close to the measured recombination value by the IST. This shows that impedance spectroscopy can be used to measure effective lifetime of the wafer using an induced junction structure prior to the formation of an actual device like the solar cell. Moreover, the series resistance (Rs), diode ideality factor (n) and barrier height (Vbi) obtained from C–V (using the IST) data as well as the I–V measurement of the device show agreement with the expected device parameters. Thus, the IST can be effectively employed as a tool in extracting many relevant characteristic parameters of the material and the device.

Item Type:	Article
Additional Information:	Copyright for this article belongs to IOP PUBLISHING.
Subjects:	Engineering Materials Science Physics
Divisions:	UNSPECIFIED
Depositing User:	Ms Neetu Chandra
Date Deposited:	31 Aug 2012 07:36
Last Modified:	31 Aug 2012 07:36
URI:	http://npl.csircentral.net/id/eprint/515

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