Surface reaction mechanism in MOCVD

The surface reaction mechanism of GaAs monolayer growth by molecular layer epitaxy (MLE) was investigated based on the application of quadrupole mass spectroscopy (QMS). The reaction of Ga(CH3)3 (TMG) and the reaction of AsH3 with the adsorbed species induced by the TMG injection 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 by TMG, and the GaCH3 produces adsorbed Ga and desorbed CH3 within 15–36 s in the temperature range of monolayer growth. When AsH3 was injected after the TMG injection, CH4 and H2 were detected. This indicates the surface reaction of GaCH3 and Ga with AsH3. The surface reaction mechanism will be discussed in detail with QMS, the growth rate measurement and optical reflection intensity measurement in MLE.