A vertical cold‐wall low‐pressure metalorganic chemical vapor deposition system is used for the growth of Sn‐dopedn‐type GaAs epilayers. Smooth and specular Sn‐doped GaAs epilayers can be easily grown. Van der Pauw Hall measurement, andI‐VandC‐Vcharacteristics show that tetraethyltin is a suitable source for GaAsn‐type dopant. Sn surface accumulation has been observed from Auger electron specroscopy (AES) and secondary ion mass spectrometry (SIMS) measurements. From infrared spectroscopy (IR) examination of the deposit on the quartz reactor wall, the decomposition of TEG is incomplete. The results of selective epitaxial growth indicate that the GaAs growth from TEG is controlled by surface kinetics. Tetraethyltin can enhance the growth rate of GaAs and decrease the As/Ga ratio and also EL2 concentration. A EL2 model is proposed.