SILICON DOPING OF INGAAS GROWN BY MOVPE USING TERTIARYBUTYLARSINE

Silicon doping of InGaAs with disilane by low pressure metalorganic va por phase epitaxy (MOVPE) using tertiarybutylarsine (TBAs) as the grou p V source has been investigated The dependence of carrier concentrati on on the substrate temperature, V/III ratio and reactor pressure was studied. The carrier concentration increases linearly with the ratio o f molar fraction of disilane to group III sources. The doping efficien cy depends not only on the substrate temperature, but also on the reac tor pressure and on the carrier gas velocity. Apparent activation ener gies of 1.1, 1.4, 2.0 eV were observed at reactor pressures of 100, 40 , 20 mbar for substrate temperatures between 590 degrees C and 640 deg rees C. The doping efficiency increases with increasing V/III ratio at a substrate temperature of 590 degrees C, and decreases slightly at 6 40 degrees C. Possible dopant incorporation mechanism was discussed. S ilicon doping efficiency is about two times higher by using TBAs inste ad of arsine.