Plasma-Cleaned InSb (112)B for Large-Area Epitaxy of HgCdTe Sensors

Plasma etching of (112)B InSb to prepare this semiconductor for the heteroepitaxy deposition of CdTe and initial studies of CdTe epilayers grown by molecular beam epitaxy (MBE) on InSb (112)B substrates cleaned with various plasma treatments are presented. X-ray diffraction rocking curve maps of the MBE CdTe epilayers on 3-inch InSb (112)B substrates have full-width at half-maxima (FWHM) values in the range of 20 arcsec to 30 arcsec. An etch pit density analysis of the 3-inch CdTe epilayers reveals a defect density of 1.0 × 10 7 cm −2 and 7.7 × 10 5 cm −2 at the center and edge of the wafer, respectively. Evaluation of a standard HgCdTe annealing process suggests that the removal of the InSb substrate is likely to be needed prior to any postgrowth annealing in Hg overpressure. Finally, we present a low-energy helium plasma exposure of wet-etched InSb (112)B substrates that provides a uniform epi-ready surface that is nearly stoichiometric, and free of oxide and residual contaminants.