Progress with surface passivation of heavily doped n+ silicon by industrial PECVD SiNx films

Significant progress in surface passivation of phosphorus diffused n⁺ silicon surfaces is reported in this work using standard industrial inline plasma-enhanced chemical vapor deposited (PECVD) silicon nitride (SiN_x) films deposited on ultrathin (~0.6 nm) chemically grown silicon oxide (SiO_x). Record low emitter saturation current density (J_0e) values of 10 and 22 fA/cm² are reported for 170-Ω/sq planar and textured n⁺ silicon, respectively. Contactless corona-voltage measurements revealed mid-gap interface defect density D_it at the Si surface to be about 1×10¹¹ eV^-1cm^-2 for SiN_x films deposited on the ultrathin SiO_x. It is explained that the surface passivation mechanism of the fabricated samples to be completely ruled by chemical passivation.