Silicon doping of InP grown by MOVPE using tertiarybutylphosphine

Disilane has been used to grow Si-doped InP by low pressure metal organic vapour phase epitaxy (LP-MOVPE). As phosphorous precursor we used tertiarybutylphosphine (TBP) and phosphine (PH₃) for comparison. Trimethylindium (TMIn) was the In source. The dependence of carrier concentration on substrate temperature, V/III ratio and reactor pressure was investigated. The Si concentration was proportional to the ratio of molar fraction of disilane to TMIn independent on the used group V precursors. The doping efficiency using TBP was much higher than using PH₃. The Si incorporation increases slightly with increasing V/III ratio independent on the group-V source. Also the electron concentration increases with increasing reactor pressure. Apparent activation energies of 1.4 eV, 1.6 eV and 1.8 eV were observed at reactor pressures of 100, 40 and 20 hPa for growth temperatures between 823 K and 883 K. Si incorporation mechanisms, which may explain the experimental results, are discussed