Inductively coupled plasma etching of through-cell vias in III–V multijunction solar cells using SiCl₄/Ar

In this work, inductively coupled plasma reactive ion etching processes with SiCl4/Ar gas chemistries were optimized to fabricate wafer-scale, high-density, small-area via-holes for InGaP/GaAs/InGaAs inverted metamorphic triple-junction solar cells. Anisotropic and smooth etching with good uniformity of both the etch profiles and etch depths across a full 4-in. wafer were obtained. By combining optical emission spectroscopy with an analytical size-effect model, calibrated end-point detection for small features is demonstrated.