Chemical polishing of CdZnTe substrates fabricated from crystals grown by the vertical-gradient freezing method |
| |
Authors: | P Moravec P Höschl J Franc E Belas R Fesh R Grill P Horodyský P Praus |
| |
Affiliation: | (1) Faculty of Mathematics and Physics, Institute of Physics, Charles University, CZ-121 16 Prague 2, Czech Republic |
| |
Abstract: | Chemical polishing is a process of crucial importance in the manufacture of epiready substrates for molecular beam epitaxy
(MBE) of high-quality HgCdTe layers. With the aim of fabrication of (211) CdZnTe substrates, we focused on the fundamental
research of polishing processes with respect to reducing subsurface damage. Wafers of the orientation (211) were prepared
from the as-grown crystals by a process flow including oriented slicing, several steps of mechanical polishing, and finally
chemical polishing. In the prechemical polishing process, several free and bound abrasives were applied to reach the surface
roughness close to 1 nm. The surface polishing treatment included testing of the surface quality after each polishing step.
We used an interferometer profiler, which yields detailed surface maps. Within chemical polishing processing, we have looked
for an optimum composition of etchant based on the bromine-methanol/ethylene glycol solution and adequate polishing pad. We
studied the substrate surface quality dependence on the rotation speed of the plate, sample loading weights, and duration
of polishing. Correlation between the final surface roughness and layer thickness removed was established. The chemical polishing
with a very low concentration of Br-methanol/ethylene glycol solution was found to yield very good CdZnTe surfaces with a
perfect flatness. |
| |
Keywords: | CdZnTe substrates chemical polishing |
本文献已被 SpringerLink 等数据库收录! |
|