CARBON DOPING AND GROWTH-RATE REDUCTION BY CCL4 DURING METALORGANIC CHEMICAL-VAPOR-DEPOSITION OF GAAS

The electrical, structural, and optical properties of GaAs grown by metalorganic chemical-vapor deposition using CCl4 have been studied and the growth rate reduction by CCl4 under various growth conditions has been investigated. Hole concentrations ranging from 2X10(16) to 1.8x10(20) cm(-3) have been obtained by varying V/III ratio and growth temperature. From Hall, x-ray, and low-temperature photoluminescence measurements, a low compensation is ensured. A growth rate reduction up to 50% has been observed. The dependence of the growth rate reduction on the growth temperature, the V/III ratio, and the CCl4 mole fraction was investigated. It is believed that the growth rate reduction is caused not by etching of solid GaAs but by reduction of Ga species through the formation of GaCl in gas phase.