A STUDY OF CHEMICAL BEAM EPITAXY OF GAAS USING TRIS-DIMETHYLAMINOARSENIC

The growth of GaAs by chemical beam epitaxy using triethylgallium and trisdimethylaminoarsenic has been studied. Reflection high-energy electron diffraction (RHEED) measurements were used to investigate the growth behavior of GaAs over a wide temperature range of 300-550 degrees C. Both group III- and group V-induced RHEED intensity oscillations were observed, and actual V/III incorporation ratios on the substrate surface were established. Thick GaAs epitaxial layers (2-3 mu m) were grown at different substrate temperatures and V/III ratios, and were characterized by the standard van der Pauw-Hall effect measurement and secondary ion mass spectroscopy analysis. The samples grown at substrate temperatures above 490 degrees C showed n-type conduction, while those grown at substrate temperatures below 480 degrees C showed p-type conduction. At a substrate temperature between 490 and 510 degrees C and a V/III ratio of about 1.6, the unintentional doping concentration is n similar to 2 x 10(15) cm(-3) with an electron mobility of 5700 cm(2)/V.s at 300K and 40000 cm(2)/V.s at 77K.