Decomposition of a Solid Solution of Interstitial Magnesium in Silicon

Abstract

The decomposition of a solid solution of interstitial magnesium Mg_i 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 Mg_i 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 E_a ≈ 1.6 eV, which is close to the previously determined diffusion activation energy of Mg_i 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.