Crystal Lattice Defects in MBE Grown Si Layers Heavily Doped with Er

Summary

The main types of crystal structure defects in [Er]>2×10¹⁹ doped layers are: (i) spherical Er and (ii) ellipsoidal ErSi precipitates, as well as (iii) ErSi₂ platelets on {111} planes. In the sample with [Er]=4x10¹⁹, small complexes consisting of tiny Er precipitates and four petals of ErSi₂ platelets have been found additionally. The layer with [Er]= 8×10¹⁸ cm⁻³ was defect free. The formation of silicides from a supersaturated solid solution and Er precipitates is accompanied by the emission of vacancies V resulting in the formation of pores, V-V and V-Er complexes.