CARBON DOPING AND ETCHING OF ALXGA1-XAS 0-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-1) WITH CARBON-TETRACHLORIDE IN METALORGANIC VAPOR-PHASE EPITAXY

Carbon doping and the parasitic growth-rate reduction with carbon-tetr achloride (CCl4) in AlxGa1-xAs was studied in the entire Al compositio n range for metalorganic vapor phase epitaxial growth. The doping effi ciency in AlGaAs was found to increase by two orders of magnitude when the Al composition in AlxGa1-xAs changed from 0 to 1. The parasitic g rowth rate reduction, however, decreased by a factor of 15 when x chan ged from 0 to 1. This reduction of growth rate was confirmed to be cau sed by the etching of the material from the surface by Cl radicals cra cked from CCl4. This strong compositional selectivity of the doping an d etching has potential implications for lateral definition of growth on patterned surfaces. The doping and etching behaviors were also stud ied as a function of the growth temperature. (C) 1997 American Institu te of Physics.