Range and standard deviation of ion-implanted Si in GaAs

Carrier-concentration profiles of Si in semi-insulating GaAs have been obtained by C-V measurement techniques. Si+ or Si++ ions were implanted at energies ranging from 50 to 600 keV, and annealing was carried out with Si3N4 encapsulants. Range parameters such as the projected range Xp and the projected standard deviation ΔXp were experimentally determined by use of depths at the peak carrier concentration and at the 1/√e value of the peak carrier concentration of the profiles. It was found that ΔXp was strongly dependent on the Cr contents of substrates while Xp was not. The measured carrier concentrations could be approximated by the Gaussian distribution, and values of Xp were in good agreement with the theoretical value of the projected range Rp. However, ΔXp tended to saturate as the incident energies increased and deviated from the theoretical value of the projected standard deviation ΔRp.