Advanced thin conformal Al2O3 films for high aspect ratio mercury cadmium telluride sensors

Abstract

Mercury cadmium telluride (HgCdTe) processing must be performed at a low temperature in order to reduce Hg depletion. To meet demand, low-temperature plasma enhanced atomic layer deposition (PE-ALD) is an emerging deposition technology for highly conformal thin films. We comparatively studied the effectiveness of low-temperature PE-ALD by measuring the ALD film roughness, thickness, and dielectric values. Conformal deposition was investigated through scanning electron microscopy images of the Al 2 O 3 film deposited onto high aspect ratio features dry-etched into HgCdTe. PE-ALD demonstrated conformal coatings of trenches, pillars and holes in advanced HgCdTe infrared sensor architectures.