HgCdTe buried planar structures fabricated by liquid phase epitaxy

摘要

This article reports the use of liquid phase epitaxy to fabricate buried HgCdTe photodiodes. Modern epitaxial techniques make possible to grow complex heterostructures with precise control of band gap and doping level profiles which can be applied for high performance optoelectronic devices. More complex heterostructures can be grown with 3 dimensional (3D) ban gap engineering using multiple epitaxy, selective growth, growth on profiled substrate and combination of these methods. We report an investigation of Hg_(1-x)Cd_xTe epitaxial layers grown on holes etched in CdZnTe(111)B substrates. Prior to growth of HgCdTe layers the substrate has been etched to form holes on 30 μm diameter and 20 μm depth. Next, 20-μm thick HgCdTe epitaxial layer has been grown by liquid phase epitaxy (LPE) from Te-rich solution. The Nomarski microscopy showed that the surface of specially prepared layers was flat and the composition of layers measured by FTIR microscopy was homogeneous. Samples were cleaved and examined in cross section by SEM.