Modeling of ideality factor value in n+--p--p+-Si structure

Abstract

This paper presents the results of computer simulation of the ideality factor of silicon n−p−p structure with iron contamination. The Solar Cells Capacitance Simulator (SCAPS) was the tool used for numerical simulation of these devices. The iron concentration range of 10 − 10 cm−3, the acceptor doping level range of 10 − 10 cm−3, the temperature range of 290− 340 K, and the base thickness range of 150 − 240 μm were used in the investigation. The double diode model was used to extract the ideality factor. The following cases were considered: (i) uniformly distributed lone interstitial iron atoms; (ii) coexistence of non-uniformly distributed Fei and FeiBs. It has been shown that the ideality factor value is determined by a hole occurring on the Fei level, a trap location, and an intrinsic recombination contribution. The increase in the base thickness leads to a decrease in n value. The sign of change in the ideality factor after FeiBs dissociation depends on temperature, doping level, and iron concentration.