Rapid vapor-phase direct diffused emitter for solar cell applications

Emitter diffusion using POCl3 or BBr3 as precursor is a time consuming process and requires chemical treatments to remove silicate glasses after the diffusion process. Moreover, no standard emitter diffusion process using BBr3 is established so far. A so called rapid vapor direct diffused emitter (RVD) might be an alternative to these POCl3 and BBr3 diffusion processes. Here, we present several RVD emitter profiles in n-type wafers achieved using the rapid thermal chemical vapor deposition (RTCVD 160) tool by varying diborane (B2H6) concentrations, peak temperatures and durations. Further, temperature induced degradation of carrier lifetimes is observed.