Silicon doping of InGaAs grown by MOVPE using tertiarybutylarsine

Silicon doping of InGaAs with disilane by low pressure metalorganic vapor phase epitaxy (MOVPE) using tertiarybutylarsine (TBAs) as the group V source has been investigated The dependence of carrier concentration on the substrate temperature, V/III ratio and reactor pressure was studied. The carrier concentration increases linearly with the ratio of molar fraction of disilane to group III sources. The doping efficiency depends not only on the substrate temperature, but also on the reactor pressure and on the carrier gas velocity. Apparent activation energies 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 degrees C. The doping efficiency increases with increasing V/III ratio at a substrate temperature of 590 degrees C, and decreases slightly at 640 degrees C. Possible dopant incorporation mechanism was discussed. Silicon doping efficiency is about two times higher by using TBAs instead of arsine.