ION-BEAM DAMAGE IN EPITAXIALLY GROWN MCT ON GAAS

Ion beam analysis has been used to investigate the epitaxial quality and compositional and thickness uniformity of epitaxial Hg1-xCdxTe (MCT) layers on GaAs substrates grown by low temperature MOCVD. To determine the effect of the ion beam on the MCT layer during a typical measurement, damage studies have been performed by channeling analysis using a nuclear microprobe. Microprobe channeling enabled high flux damage to be investigated. Areas of crystal ranging from approximately 30 x 30-mu-m2 to 260 x 260-mu-m2 were scanned using both 2.0 MeV H+ and He+ ions and the chi(min) measured as a function of ion beam dose. Macrobeam channeling was also performed with an unscanned beam of 1 mm spot size. The results indicate the acceptable range of dose for ion beam analysis.