Carbon doping and etching in GaxIn1−xAsyP1−y on GaAs substrates using CBr4 by metalorganic chemical vapor deposition
Carbon doping and etching by CBr4 were studied for GaxIn1−xAsyP1−y (0≤y≤1) on GaAs grown by metalorganic chemical vapor deposition. It was found that the hole concentration drastically decreases with decreasing y when the flow rate of CBr4 is constant. When y is under 0.5, the conduction type of GaInAsP changes ton-type. In the region of 0<y<0.6, the surface morphology was degraded and the carrier compensation became higher than could be estimated from the C concentration. This seems to be due to the micro defects because this range of composition is within the unstable region which is theoretically predicted. The etching effect by CBr4 was observed during the growth. The rate of etching for InAsP component is about three times larger than that for the GaAsP component. The thermodynamic analysis suggests that the etching is due to the increase of the partial pressure of GaBr and InBr.