SURFACE-REACTION MECHANISM IN MOCVD

The surface reaction mechanism of GaAs monolayer growth by molecular l ayer epitaxy (MLE) was investigated based on the application of quadru pole mass spectroscopy (QMS). The reaction of Ga(CH3)(3) (TMG) and the reaction of AsH3 with the adsorbed species induced by the TMG injecti on on GaAs (001) have been studied by the measurement of the desorbed species by QMS. It is shown that GaCH3 is an adsorbed species formed b y TMG, and the GaCH3 produces adsorbed Ga and desorbed CH3 within 15-3 6 s in the temperature range of monolayer growth. When AsH3 was inject ed after the TMG injection, CH4 and H-2 were detected. This indicates the surface reaction of GaCH3 and Ga with AsH3. The surface reaction m echanism will be discussed in detail with QMS, the growth rate measure ment and optical reflection intensity measurement in MLE.