Formation rates of iron-acceptor pairs in crystalline silicon

Abstract

The characteristic association time constant describing the formation of iron-acceptor pairs in crystalline silicon has been measured for samples of various p-type dopant concentrations and species ͑B, Ga, and In͒ near room temperature. The results show that the dopant species has no impact on the pairing kinetics, suggesting that the pairing process is entirely limited by iron diffusion. This conclusion was corroborated by measurement of the activation energy of pair formation, which coincides with the migration enthalpy of interstitial iron in silicon. The results also indicate that the pair-formation process occurs approximately twice as fast as predicted by a commonly used expression.

Accurate measurement of the formation rate of iron–boron pairs in silicon

“…The same methodology applied by Macdonald et al [6] to extract  assoc from the effective lifetime exponential decay curves has been used in this paper. figure 3.…”

“…[2,3,4] However, recent measurements of Fe i -B association time constants ( assoc ) utilizing a temperature controlled WCT-100 Sinton Consulting instrument [5], have indicated that the pre-factor in the equation published by Macdonald el al. [6] (5x10 5 cm -3 K -1 ) requires some adjustment. In addition, the original measurements were accurate to ±3K.…”

Effect of Ge doping on the kinetics of iron–boron pair association and dissociation in photovoltaic silicon

“…It has been reported that the association of FeB pairs needs an activation energy of 0.60 eV [2]. This process is limited by the Fe diffusion towards substitutional B in silicon [2,9,10], with a diffusion constant (D 0 ) being in the range of 0.6 À1.8 Â 10 À 3 cm 2 /s [2,11]. For the dissociation of FeB pairs, the activation energy is 1.17 À 1.2 eV, and the corresponding attempt frequency is 1.8 À5 Â 10 10 s À 1 [2].…”

Eliminating Light-Induced Degradation in Commercial p-Type Czochralski Silicon Solar Cells

“…The benefit of using gallium-doped wafers is that they are free of any B-O related LID effects. However, like boron-doped wafers, they are susceptible to the formation of acceptor-iron pairs [53,54]. A weakness of gallium-doped ingots is the substantially lower segregation coefficient for gallium (8 × 10 −3 ) than that for boron (0.8) [55,56].…”