Incorporation modes of silicon in GaAs: Si grown by metalorganic vapor phase epitaxy

The incorporation of silicon from SiH4 in GaAs has been studied on a wide r ange of growth conditions by atmospheric pressure metalorganic vapor phase epitaxy (AP-MOVPE). The highest free carrier concentration exceeds 1 x 10(1 9) cm(-3) Compensation ratios appear to be strongly dependent on the SiH4 p artial pressure. The relatively high compensation ratios essentially origin ate from the amphoteric behaviour of silicon. The temperature dependence of silicon doping has been investigated in the range 650 degrees C to 765 deg rees C with various silane partial pressures. The activation energy of Si i ncorporation varies from 0 to 2.2 eV. The dependence of the free electron c oncentration on the arsine partial pressure (PAsH3) leads to the empirical relationship: n = aP(AsH3) + bP(AsH3)(-4/3), which describes the relationsh ip between silicon doping concentration and arsine partial pressure.