A COMPARISON OF THE DIFFUSION OF IODINE INTO CDTE, HG0.8CD0.2TE AND ZN0.05GD0.95TE

Studies on the diffusion of iodine into CdTe, mercury cadmium tellurid e (Hg0.8Cd0.2Te, referred to as MCT) and zinc cadmium telluride (Zn0.0 5Cd0.95Te, referred to as ZCT) in the temperature range of 20 to 600 d egrees C are compared and discussed. The concentration profiles were m easured using a radiotracer sectioning technique. As with the diffusio n studies using the halogens into CdTe, the profiles were composed of four parts to which a computer package consisting of the sum of four c omplementary error functions (erfc) gave satisfactory fits. The diffus ivity for the diffusion of iodine into MCT was faster than for the dif fusion into CdTe, which was faster than for the diffusion into ZCT. Th e high diffusivity for the fastest profile part at 20 degrees C indica tes that when iodine is diffused from the vapor into these materials, it is not a suitable long term stable dopant in devices where sharp ju nctions are required.