Gettering Efficacy of APCVD-Based Process Steps for Low-Cost PERT-Type Multicrystalline Silicon Solar Cells

Gettering efficacy of an APCVD glasses based stacked co-diffusion for bifacial mc-Si PERT solar cells

“…Moreover, PSG on only one side of the sample is sufficient to (nearly) reach the gettering efficacy of the both sided stacked PSG diffusion. These findings are consistent with the non-stacked APCVD glasses based co-diffusion gettering results reported in [2].…”

“…However, p-type mc-Si features a wide variety of (metal) impurities which makes efficient gettering inevitable. Efficient gettering in APCVD glasses based co-diffusion works in principle and the process is suitable for PERT solar cell production [2]. Though, the thermal load of wafers at different positions in a stacked co-diffusion may differ among each other and from standard co-diffusions.…”

Etch Pit Density Reduction in POCl3 and Atmospheric Pressure Chemical Vapor Deposition‐Gettered mc‐Si

“…For gettering, here, an industry standard POCl 3 diffusion was used, whose gettering properties on this material are well known . Results show a comparable overall EPD for all the different etching solutions as well as similarly strong EPD reduction for all etchants (Figure ).…”

“…The co-gettering step results in typical improvements in τ eff and [Fe i ]. [1] EPD measurements after Secco etch, executed on the P-gettered wafer side, show that low lifetime and high [Fe i ] regions typically correlate with regions of high EPD and that such regions remain inferior to their surroundings after co-gettering. [16] Apart from this well-known gettering behavior, we additionally observe that EPD in regions of mid and low EPD is reduced by about one third after APCVD gettering.…”

“…With the possibility of one-sided doping glass deposition and the separation of the doping glass deposition from the diffusion step, multiple high temperature steps can be combined into a single co-diffusion step. Co-diffusion gettering is known to increase the material quality of multicrystalline silicon, [1] and gettering [2] of the mc-Si material by means of phosphorous- [3,4] and boron-diffusion [5] are well researched. Although effects of phosphorous diffusion gettering on metallic contaminations have been studied and correlated with measurements of etch pit density (EPD), [6] there is a lack of literature on the interplay of gettering procedures with EPD measurements.…”