Decomposition of a Solid Solution of Interstitial Magnesium in Silicon

The decomposition of a solid solution of interstitial magnesium Mgi in silicon is studied. Float-Zone dislocation-free single-crystal n-Si with a resistivity of ~8 × 103 Ω cm and oxygen and carbon contents of ~5 × 1014 cm–3 and ~1 × 1015 cm–3 is used in the experiments. The samples are doped using the diffusion sandwich method at T =1100°C followed by quenching. Decomposition of the supersaturated Mgi solid solution is studied by observing the kinetics of increasing the resistivity of doped samples resulting from their annealing in the range T= 400–620°C. It is found that the decomposition is characterized by an activation energy of Ea ≈ 1.6 eV, which is close to the previously determined diffusion activation energy of Mgi in silicon. It is also shown that Si:Mg exhibits stable properties at temperatures not exceeding 400°C, which is important for its possible practical application.