DocumentCode :
2311860
Title :
Degradation free SiO2 passivation layer oxidized by TCA process
Author :
Uematsu, T. ; Nagata, Y. ; Ohtsuka, T. ; Warabisako, T. ; Nomura, H. ; Iga, T. ; Saitoh, T.
Author_Institution :
Res. Lab., Hitachi Ltd., Ibaraki, Japan
fYear :
1993
fDate :
10-14 May 1993
Firstpage :
352
Lastpage :
355
Abstract :
Degradation of the Si/SiO2 interface in solar cells induced by sunlight irradiation can be eliminated by controlling the concentration of 1.1.1. trichloroethane (TCA) in the oxidation ambient. Despite the higher carbon concentration, the oxide which was grown 48 hours after the TCA cleaning showed no evident light degradation. A low interface trap density, Dit, was obtained for this Si/SiO2 interface. Bias light dependence of the surface recombination velocity for such degradation-free SiO2 layers was intensively analyzed by measuring effective lifetimes. The mechanism that limits fill factors in recent high-efficiency one-sun solar cells is discussed quantitatively in terms of the dependence of the surface recombination velocities on excess carrier concentration. It was clarified that even with such a small Dit, a high surface recombination velocity will result at the SiO2/Si interface with the excess carrier concentration under Vop condition
Keywords :
IV-VI semiconductors; carrier lifetime; electron-hole recombination; elemental semiconductors; oxidation; p-n homojunctions; passivation; semiconductor device models; semiconductor device testing; silicon; silicon compounds; solar cells; 1.1.1. trichloroethane; Si-SiO2; Si/SiO2 interface; bias light dependence; cleaning; degradation-free; effective lifetimes; excess carrier concentration; fill factors; interface trap density; open circuit voltage; oxidation; passivation layer; semiconductor; solar cells; sunlight irradiation; surface recombination velocity; Cleaning; Degradation; Furnaces; Hydrogen; Laboratories; Lifetime estimation; Oxidation; Passivation; Power lasers; Wavelength measurement;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Photovoltaic Specialists Conference, 1993., Conference Record of the Twenty Third IEEE
Conference_Location :
Louisville, KY
Print_ISBN :
0-7803-1220-1
Type :
conf
DOI :
10.1109/PVSC.1993.347157
Filename :
347157
Link To Document :
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