Sticking behavior of the dopants Si, C, and Be upon re-evaporation of individually doped GaAs(1Â 0Â 0)

The behavior of the dopants Si, C, and Be upon re-evaporation of correspondingly doped GaAs was studied. The samples were prepared on semi-insulating GaAs (1 0 0) by using molecular beam epitaxy (MBE) technique and focused ion beam (FIB) implantation, and were studied by Hall measurement and Secondary Ion Mass Spectroscopy. It was found that a significant fraction of dopant atoms (Si, C, or Be) was not desorbed when the doped material was re-evaporated. It was also found that after re-evaporation of the doped layer, Si- and Be-doped samples still were electrically conducting, but the C-doped samples were not. It was also found that Si-doped sample became nonconducting if the re-evaporation thickness was much larger than that of the doped layer. The comparison of Hall and Secondary Ion Mass Spectroscopy data shows that the electrical activation for all the three dopant species decreases after re-evaporation. The sticking behavior of dopants Si, C, and Be upon re-evaporation of doped GaAs is proposed to be attributed to the lower volatility of elements Si, C, and Be compared to Ga and As.