Bridgman growth and assessment of CdTe and Cd1-yZnyTe crystals

摘要

Abstract: In order to meet with the epitaxial growth of large area Hg$-1$MIN@x$/Cd$-x$/Te (MCT) with various compositions for infrared focal plane arrays, CdTe and Cd$-1$MIN@y$/Zn$-y$/Te (y $EQ 0.020, 0.025 and 0.040 for various x) crystals with 120 mm length and 20 - 40 mm diameter have been successfully synthesized and grown by the vertical Bridgman method. These crystals were grown unseededly or seededly and free of any macroscopic defects e.g. micro-cave and crackles. Wafers with areas from 12 $MUL 18 mm$+2$/ to 30 $MUL 35 mm$+2$/ in the $LS@111$GRT orientation have been obtained from large grain of the ingot. Effects of changing the ampoule base shape upon the crystal growth have also been investigated. A necked ampoule bottom is preferred to ones employing seeding. Assessments of the samples have included infrared transmission (range 2.4 - 24 $mu@m), etch pit density, X-ray photography and three-crystal rocking curve measurement. Good quality MCT epitaxial films (areas of 12 $MUL 18 mm$+2$/ and 20 $MUL 20 mm$+2$/), as demonstrated by good surface topography, electrical parameters, have been grown by liquid phase epitaxy and metal organic chemical vapor epitaxy onto CdTe(CT) and Cd$-1$MIN@y$/Zn$-y$/Te(CZT) substrate materials produced in our study.!11