Temperature-Gradient Post-Growth Annealing Of Cdmnte Wafers For Nuclear Radiation Detection Applications

Cadmium Manganese Telluride (CdMnTe) is one of the semiconductor materials recently being developed as X-ray and gamma-ray detectors capable of operating at room temperature. This paper presents the results of temperature gradient post-growth annealing of CdMnTe crystals grown by Bridgman technique. Migration of Te inclusions from the low-temperature side to the high-temperature side of CdMnTe wafers was recorded for an annealing temperature of 715 degrees C at a temperature gradient of 24 degrees C/cm and annealing time of 30 minutes. Size reduction and elimination of Te inclusions were also recorded for a CdMnTe wafer annealed at 730 degrees C with a temperature gradient of 18 degrees C/cm for 18 hours. A two-dimensional analysis of an 810 x 1350 mu m(2) sample area showed a 76% reduction in the Te-inclusion concentration.