Defect characterization and composition distributions of mercury indium telluride single crystals

A mercury indium telluride (MIT) ingot was grown by the vertical Bridgman method. The defects in MIT crystals were characterized by the chemical etching method. A defect etchant for MIT crystals was developed. The etch pits of dislocations, microcracks and boundary was observed by scanning electron microscopy. It was elucidated that the etch pits density of dislocations of MIT wafers was about 4×10⁵ cm^-2. Te and In reduced at the grain boundaries, but were homogeneously distributed within the grains in the as-grown MIT crystals. The distribution of In in MIT crystals along the growth direction and radial direction was analyzed by electronic probe microscopy. It was found that In concentration was higher in the initial part and lower in the final part of the MIT ingot, which indicated that the segregation coefficient of In in MIT crystals was 1.15. The radial In concentration increased from the center to edge of the wafers and homogeneous in the middle part.