Composition control and surface defects of MBE-grown HgCdTe

The results on composition control and surface defect study of molecular be am epitaxial (MBE)-grown Hg1-xCdxTe are described. In the long wavelength r egime, the standard deviation in x values determined by FTIR and ellipsomet ry measurements was 0.013. Good composition reproducibility was achieved. A variety of surface defects was observed and their origins are discussed. T he optimized growth window for obtaining a good morphological surface was d etermined. By careful efforts in substrates preparation as well as growth c ontrol, the averaged density of surface defects (>2 mum) for 2 in 10 mum-th ick HgCdTe wafers was determined to be 300 cm(-2). LW 256 x 1 linear focal plane arrays were fabricated on MBE-grown HgCdTe epilayers. An average dete ctivity D-lambda* of 3.5 x 10(10)cm Li root Hz W-1 with a non-uniformity fa ctor of 8.8% was obtained. (C) 2001 Elsevier Science B.V. All rights reserv ed.