Effect of Pressure on Arsenic Diffusion in Germanium: Evidence Against Simple Vacancy Mechanism

Abstract

We have measured the effect of pressure on As diffusion in Ge. Diffusion anneals on ion-implanted samples were carried out in a high temperature diamond anvil cell using fluid argon as a clean, hydrostatic pressure medium. At 575 degree Celsius over the pressure range 0.1 to 4 GPa, pressure slightly enhances the diffusivity, characterized by an activation volume of -1.7±1.4 cm^3/mole or -0.12±0.10 times the atomic volume of Ge. The results call into question the prevailing view that diffusion of group III, IV and V elements is mediated entirely by vacancies. Potential explanations of these results are discussed.