Previous studies had indicated that Mg, when diffused into Si, could pair with dispersed O in the crystal to form Mg-O complex impurities. Recently, Mg had been successfully introduced into Si containing O as well as group-III impurities. For the first time, the excitation spectrum of singly-ionized Mg-O complex impurities was observed. This clearly demonstrated that the Mg-O complex impurity was a double donor in Si. The experimental results also showed that the ionization energy of the singly-ionized Mg-O donor was 0.2749eV; which was slightly larger than that of the singly-ionized Mg donor in Si.

Singly Ionized Magnesium-Oxygen Complex Impurities in Silicon. L.T.Ho: Physica Status Solidi C, 2003, 0[2], 721-5