Relationship between impurity (B or P) and carrier concentration in SiGe(C) epitaxial film produced by thermal treatment

Relationship between impurity (B or P) and carrier concentration in Si1 x yGexCy epitaxial films (0:22 x 0:7, 0 y 0:02) produced by thermal treatment has been investigated. In the case of the B-doped Si1 xGex films with B concentration of 1021 cm 3, the carrier concentration slightly decreases with increasing temperature up to 800 8C. Because the lattice constant of the film becomes larger with heat treatment, it is suggested that B clustering proceeds with heat treatment, in other words, the epitaxial film is grown in a non-equilibrium for B. In the case of the P-doped Si1 xGex films with P concentration of 1020 cm 3, the carrier concentration scarcely changes with heat treatment for lower Ge fraction (x 0:44). For higher Ge fraction (x ¼ 0:7), the carrier concentration becomes two times higher than that of as-deposited film after heat treatment at 800 8C. Because the lattice constant of the film becomes smaller with heat treatment, it is suggested that the solid solubility of electrically active P atoms becomes higher due to the generation of substitutional P atoms at higher temperature. In the P-doped Si0.54Ge0.44C0.02 film, it is considered that the generation of substitutional P atoms is enhanced by the localization of C atoms into the interstitial site due to heat treatment. # 2003 Elsevier B.V. All rights reserved.