Characterizing Point Contacting by Localized Dielectric Breakdown and Its Use in Silicon Solar Cell Applications

The point contacting by localized dielectric breakdown (PLDB) method utilizes a dielectric breakdown above a locally doped region to form ohmic contacts for a solar cell rear surface. This article describes the design and fabrication of the PLDB solar cells and the contact properties characterization. A complete solar cell fabrication process applying PLDB as a rear contact design was developed, with the demonstration of an 18.0% proof-of-concept PERC structure PLDB solar cell. Two major loss mechanisms in the fabricated solar cell were characterized to be a high series resistance and nonideal recombination. By modulating the local boron doping profile with acidic etching, the impact of the surface doping concentration on local contact recombination and contact resistivity was investigated, resulting in an estimated contact resistivity of approximately 5 mΩ·cm
²
and contact recombination of approximately 600 fA/cm
²
. With these metrics, modeling suggests that by optimizing the contact pitch of our solar cells, efficiencies of up to 24% are well achievable for this low-temperature contacting method.