Effect of Operating Pressure on the Properties of GaAs Grown by Low-Pressure MOCVD

Undoped GaAs epitaxial layers were grown by low-pressure MOCVD in a wide range of operating pressure (3×10-3 to 75 Torr). These epitaxial layers had smooth surfaces. Conductivity of the epitaxial layers grown under the same [AsH3]/[TMG] ratio (=75) changed from n-type to p-type at about 5×10-1 Torr as operating pressure was reduced. Low temperature photoluminescence spectra indicate that carbon is the dominant acceptor and its concentration increases as operating pressure is reduced.