The use of oxynitrides for the fabrication of buried contact silicon solar cells

Comparison of TiO2and other dielectric coatings for buried‐contact solar cells: a review

“…82 In comparison, a 100-nm-thick SiO 2 film resulted in a sheet resistance of 40 /square under the same diffusion process. 82 The etch rate in buffered HF was 1Á6 nm/ min for SiON films, as opposed to 22Á4 nm/min for SiO 2 films. In addition, SiON films successfully withstood all other chemicals used in the standard BC fabrication sequence.…”

“…37 SiON films can be deposited via various deposition techniques, including PECVD, LPCVD and nitridation of SiO 2 films. 37,47,82 SiON was first implemented into the double-sided buried-contact (DSBC) structure by Ebong et al 82 A very thick SiO 2 layer (up to 1m m) is required on the surfaces of the DSBC device in order to mask all the boron and phosphorus diffusions and metal plating steps. The thick oxide reduced the performance of the textured solar cell due to stress arising from the thermal expansion coefficient mismatch.…”

“…85 The films were initially thermally grown as SiO 2 and then subjected to an ammonia ambient for 10 h at 1150 C to form SiON. 82 The oxynitride film consumes the SiO 2 layer and grows from the interface, and it was observed that the surface passivation properties of the SiON were poor, corresponding to a surface recombination velocity of 10 4 cm/s. In addition, Ebong et al determined that the lengthy ammonia annealing step also reduced the bulk minority-carrier lifetime.…”

“…In addition, Ebong et al determined that the lengthy ammonia annealing step also reduced the bulk minority-carrier lifetime. 82 Research has demonstrated that a 120-nm-thick SiON film successfully prevented a 4Á5 h phosphorus diffusion performed at 940 C from reaching the silicon wafer. 82 In comparison, a 100-nm-thick SiO 2 film resulted in a sheet resistance of 40 /square under the same diffusion process.…”

“…82 Research has demonstrated that a 120-nm-thick SiON film successfully prevented a 4Á5 h phosphorus diffusion performed at 940 C from reaching the silicon wafer. 82 In comparison, a 100-nm-thick SiO 2 film resulted in a sheet resistance of 40 /square under the same diffusion process. 82 The etch rate in buffered HF was 1Á6 nm/ min for SiON films, as opposed to 22Á4 nm/min for SiO 2 films.…”