Raman spectroscopic study of HgCdTe epilayers for infrared detector array fabrication

Micro-Raman spectroscopy was used to evaluate the surface quality of Hg1−xCdxTe (x = 0.3) epitaxial layers polished with chemo-mechanical and free chemical etching processes. Raman technique has been employed to monitor the HgCdTe detector array fabrication process to ensure epilayer surface devoid of impurities and minimal damage. Chemical etching with bromine-methanol solution is seen to leave residual damage or non-stoichiometric HgCdTe surface layer indicated by an asymmetrical broadening and down shift in all Raman peaks. A peak at 112 cm−1 as defect mode or due to disordering on the epilayer surface has been noticed.