Improvement of hydrogen passivation via the template of acid textured surface

In solar cell manufacturing, surface texturing plays an important role in light trapping. Besides optical performance, it was revealed to be also critical to passivation performance of solar cells in this study. Among wafers textured with different chemicals (HNO
₃
, KOH and KOH with IPA) and deposited with PECVD SiN
_x
:H films, the acid HNO
₃
textured wafers showed the highest bulk lifetime, while the alkaline KOH textured ones showed the lowest surface recombination velocity (SRV). With the advantage of bulk lifetime improvement from acid textured surface, an additional passivation process via the template of acid textured surface prior to KOH or KOH+IPA texturing was testified to be able to enhance bulk lifetime and reduce SRV of wafers. Besides bulk lifetime and SRV, the density of interface trap (D
_it
) also shows the same correlation with the passivation performance mentioned above, as revealed by CV measurement in this study.