Chemical Thermodynamic Analysis of Silicon Doping in MOCVD of GaAs System

With chemical thermodynamic method,enthalpies,entropies and heat capacities of（SiH3）nAsH3-n（1≤n≤3）,（CH3）mSiH4-m（1≤m≤4）and their radicals were calculated.Homogeneous reactions equilibrium of 65gas phase species in SiH4（or Si2H6）doped MOCVD GaAs by TMG and AsH3 system was analyzed,the re-lations of gas phase partial pressures with growth temperatures and input partial pressures were calculated.When the gas phase is saturated with a GaAs:Si solid,the gas phase partial pressures and solid phase siliconimpurity(SiGa-As,Ga-SiAs,SiGa-SiAs)concentrations were calculated under different growth temperatures andinput partial pressures.With the above results,some of the Si doping behavior in MOCVD of GaAs are ex-plained.