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Cadmium Zinc Telluride (Cd1-xZnxTe or CZT) is a ternary II-VI compound semiconductor material that has been widely used in infrared detector applications for many years. Due to its lattice spacing, CZT is the substrate of choice for stabilizing Mercury Cadmium Telluride (Hg1-xCdxTe or MCT) crystal layer growth where the lattice matching reduces stress during detector growth processes for high performance infrared detectors and focal plane (FPA) arrays used in guidance systems and a wide array of IR applications. The manufacturing of high performance MCT IR detectors requires CZT substrates of high quality for both bulk and surface conditions thus enabling high quality MCT epitaxial layer crystallinity and low defectivity. In this work, we report on results on bulk CZT material grown using the Travelling Heater Method (THM) that are suitable for infrared focal plane array (IRFPA) detector applications. This proven crystal growth process has been used to manufacture CZT substrates meeting industry requirements of IR transmission, tellurium precipitate size, dislocations and of larger single crystal area. We will present results on chemomechanical (CMP) polishing of CZT substrates of square, rectangular and state-of-the-art round geometries utilizing standard production tool sets that are identical to those used to produce epitaxy-ready surface finishes on related IR compound semiconductor materials such as GaSb and InSb. Surface quality will be assessed by various analytical and microscopy techniques to validate the suitability of this material for epitaxial growth.
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