The Activation Energy of Phosphorus Donors in Silicon‐Rich Silicon–Germanium Alloys

Abstract

Abstract The activation energy of phosphorus substituted into Si 1− x Ge x alloys (0 ≦ x ≦ 0.27) is investigated by IR absorption. A weak shift of the activation energy with germanium content is found: E (A 1 ) = (45.5 − 26 x ) meV. This can be explained by multivalley effective mass theory with a phenomenological central cell potential which does not depend on alloy composition within the investigated range. The experiments show that P atoms are distributed at random in the alloy and that their positions are uncorrelated to those of the Ge atoms.