Integrated technology in MCT/GaAs and MCT/Si for medium and long wavelength infrared

MCT layers were grown by MOCVD on CdTe, GaAs and GaAs/Si for device processing. Both (111) and (100)MCT were grown on GaAs and the relative merits of the two orientations are discussed. The effects of the substrate preparation, pre-bake, nucleation and buffer growth conditions led to (100)MCT layers being p-type as grown with FWHM's of 80 to 90 arc seconds. CdTe was grown on (311)A and B GaAs. The CdTe adopts one of several orientations (100) or 3 to 4 DEG (311) and is untwinned with a relatively smooth surface morphology. Continuing studies of CdTe growth on Si indicate that the nucleation temperature should be higher than 450 C. Annealing studies were carried out to establish material of a consistent p-type carrier concentration for processing, and to understand the diffusion mechanism within the material. A reproducible p-type anneal was established. Linear arrays of LWIR and MWIR diodes were n formed in MCT/GaAs by diffusion through a ZnS mask. 77K R sub o A products obtained over a range of cut-off wavelengths are comparable to the state-of-the-art literature values. R sub o A's of 10 ohm cm sq were obtained for arrays with a 11 micron cutoff.