DIFFERENCE OF REACTION BETWEEN ASH3 AND ARSENIC VAPOR FROM AS METAL IN VAPOR-PHASE EPITAXY OF GAAS

GaAs was grown by mixing either AsH3 or arsenic vapor (As4 or As2) from As metal with GaCl3 supplied by He or H2 gas. When the carrier gas of GaCl3 was He, GaAs was grown when AsH3 gas was used. Gas etching of the substrate occurred if As metal was used as the As source. When the carrier gas of GaCl3 was H2, however, GaAs was grown by using either AsH3 or As metal, but dependence of the growth rate on the substrate position was different. These results indicate that AsH3 is not completely decomposed into As4 or As2 but directly reacts with GaCl3 and GaCl, while the arsenic vapor (As4 or As2) can react only with GaCl but not with GaCl3. © 1990.