Selective growth of AlGaInAs/InP on masked substrate is investigated by low-pressure metalorganic chemical vapor deposition (MOCVD). Tetrabromocarbon (CBr4) is introduced into the reactor during epitaxial growth as etching gas. The etching action of CBr4 on AlGaInAs grown on planar substrate only affects In atoms, and has little influence on Al and Ga. Selective area growth of AlGaInAs multi-quantum wells (MQWs) on masked substrate is carried out by introducing CBr4 during growth of Al-containing layers except wells. Polycrystals on the dielectric mask decrease with CBr2 flow rate and complete selectivity is achieved with CBr4 flow rate of 3.2 mu mol/min when the growth temperature and the growth rate are 680 degreesC and 30 nm/min, respectively, which correspond to our optimum condition for the growth of AlGaInAs. From the results of photoluminescence and broad-type laser diode of MQW, the introduction of CBr4 does not seem to degrade the crystallinity of AlGaInAs/InP.