ULTRA-HIGH-PURITY STARTING MATERIALS FOR INFRARED (IR) DETECTOR CRYSTAL GROWTH.

CURRENT IR FOCAL PLANE ARRAYS REQUIRE DETECTOR MATERIAL THAT IS NEARINTRINSIC IN CARRIER CONCENTRATION, OF A LOW DISLOCATION DENSITY, AND, MOST IMPORTANTLY, FREE OF PRECIPITATES AND IMPURITY CLUSTERS. ALTHOUGH HIGHER PURITY STARTING MATERIALS ARE REQUIRED TO ACHIEVE NEAR-INTRINSIC CARRIER CONCENTRATIONS, NON-ELECTRICALLY ACTIVE IMPURITIES SUCH AS IRON, CHROMIUM, SILICON, NICKEL, MANGANESE AND OTHERS CAN HAVE A PROFOUND NEGATIVE EFFECT ON FINAL DEVICE PERFORMANCE. THIS PROGRAM EXPLOITS A NOVEL TECHNIQUE FOR REMOVING MANY IMPURITIES, INCLUDING OXYGEN, FROM II-VI STARTING MATERIALS. A DISTILLATION/ZONE REFINING TECHNIQUE IS NOT SUFFICIENT TO PRODUCE THE QUALITY OF STARTING MATERIAL NEEDED FOR SECOND GENERATION FOCAL PLANE ARRAYS. AN ELECTROMIGRATION PROCESS FOLLOWED BY DISTILLATION THROUGH AN OXYGEN GETTERING MEDIA IS EXPLOITED AS A METHOD OF ACHIEVING HIGHER PURITY MATERIALS.