Anisotropic and low damage III-V/Ge heterostructure etching for multijunction solar cell fabrication with passivated sidewalls

This article presents a complete plasma etching process to etch high aspect ratio patterns on III-V/Ge solar cell heterostructure with low damage for the fabrication of multijunction cells through via contact architecture. A SiCl4/H2 chemistry was studied different hydrogen dilutions within (0%, up 67%) and cathode temperatures (20∘C, 200∘C). choice creates SiClx-based inhibiting layer sidewalls that promotes anisotropic epitaxial heterostructure. The study suggests flow temperature reduce chemical reactions create sidewall erosion. appears provide passivation non-radiative defects III-V during process. triple junction standard grid line busbar front back contacts have been fabricated via-holes were plasma-etched active layers in order investigate impact photovoltaic performance. results demonstrate enables an open-circuit voltage increase persists even after 5 months. can also be used mesa step contacts. Thus, it could appealing pathway conversion efficiency state-of-the-art To process, liner is protect properties time-multiplexed Ge proposed finalize patterning open towards dicing.