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Defects in oxidized p-type Si wafers observed by surface photovoltage spectroscopy

 
: Kolkovsky, Vladimir

:

Physica status solidi. A (2019), Online First, 17 pp.
ISSN: 0031-8965
ISSN: 1862-6300
ISSN: 1521-396X
ISSN: 1862-6319
English
Journal Article
Fraunhofer IPMS ()
silicon; SPV; defect; diffusion length

Abstract
Surface photovoltage spectroscopy (SPV) is widely used for semiconductor characterization in modern microelectronics. In the present study we report the results of a comprehensive SPV analysis of oxidized n- and p-type Czochralski (Cz) Si wafers with an oxygen concentration of about 5-7×1017 cm-3. We demonstrate that the oxidation of the wafers with different H2/O2 ratios can significantly influence the diffusion length of minority carriers in p-type Si. We explain this effect by the formation of OH-related defects which are strong recombination centers in such wafers. In addition, a significant degradation of the diffusion length of minority carriers was observed in oxidized p-type Si wafers after annealing at 90 °C and a subsequent illumination at room temperature. This degradation was found to be independent on oxide growth conditions and it was not observed in n-type wafers. We correlate this degradation with the presence of low concentrations of interstitial Fe (<1011 cm-3) in some wafers and with BO-related defects in some other wafers. Surface photovoltage spectroscopy (SPV) is widely used for semiconductor characterization in modern microelectronics. In the present study we report the results of a comprehensive SPV analysis of oxidized n- and p-type Czochralski (Cz) Si wafers with an oxygen concentration of about 5-7×1017 cm-3. We demonstrate that the oxidation of the wafers with different H2/O2 ratios can significantly influence the diffusion length of minority carriers in p-type Si. We explain this effect by the formation of OH-related defects which are strong recombination centers in such wafers. In addition, a significant degradation of the diffusion length of minority carriers was observed in oxidized p-type Si wafers after annealing at 90 °C and a subsequent illumination at room temperature. This degradation was found to be independent on oxide growth conditions and it was not observed in n-type wafers. We correlate this degradation with the presence of low concentrations of interstitial Fe (<1011 cm-3) in some wafers and with BO-related defects in some other wafers.

: http://publica.fraunhofer.de/documents/N-549670.html