Semi-insulating buffer layer technology

Semi-insulating buffer layer technology describes a study of undoped and intentionally doped epitaxial buffer layers grown on lightly chromium doped horizontal Bridgman and undoped LEC substrates. Specific effects of substrate impurity redistribution from bulk substrates are described by improved characterization techniques such as SIMS depth profiling, 4K Photoluminescence, Photo Induced Transient Spectroscopy (PITS) and Spark Source Mass Spectrometry (SSMS). Important correlation of dominant impurity centers has been established by Dark Conductivity Measurements. An important discovery of Fe redistribution in epitaxial layers during vapor phase growth was made by detailed chemical optical and electrical transport measurements on undoped epitaxial layers. An assessment of the effects of Oxygen doping in VPE GaAs was made using 18O(2) which resulted in the identification of an oxygen 2- related deep donor at Ec-0.67 eV. P-type conductivity resulting from oxygen 2 doping was shown to be due to a dominant Fe(2+) center. Effects of carrier removal by oxygen 2 doping were also shown.