Relationship between characteristics of steady and nonsteady impurity capture processes in molecular beam crystallization

Abstract

Doping processes using molecular beam epitaxy are considered using a model of impurity in fractures. Expressions for depth of the transition region dt the steady state impurity concentration in the crystal xBst and the insertion coefficient KB, all considering fluctuations in the fracture position, are analyzed. A precise expression, convenient for making estimates, is presented for the interrelationship of these characteristics. It is shown that in the region of low crystallization temperatures T and growth rates R typical of molecular beam epitaxy, the transition region thickness dt is proportional to 1/Ki, where the insertion coefficient depends on R and T. A connection between growth rate R dependences of transition region thickness dt and steady state impurity concentration xBst is noted. The results obtained are compared with experiment and results of other impurity capture models.