MBE HgCdTe on alternative substrates for FPA applications

Results of first-principles calculations and experiments focusing on molecular beam epitaxy (MBE) growth of HgCdTe on the alternative substrates of GaAs and Si are described. The As passivation on (2 x 1) reconstructed (211) Si and its effects on the surface polarity of ZnTe or CdTe were clarified by examining the bonding configurations of As. The quality of HgCdTe grown on Si was confirmed to be similar to that grown on GaAs. Typical surface defects in HgCdTe and CdTe were classified. Good results for uniformities of full width at half maximum (FWHM) values of x-ray rocking curves, surface defects, and x values of Hg1-xCdxTe were obtained by refining the demanding parameters and possible tradeoffs. The sticking coefficient of As-4 for MBE HgCdTe was determined. The effects of Hg-assisted annealing for As activation were investigated experimentally and theoretically by examining the difference of the formation energy of As-Hg and As-Te. Results of focal-plane arrays (FPAs) fabricated with HgCdTe grown on Si and on GaAs are discussed.