Mechanical Strength and Dislocation Velocities in GeSi Alloys

Abstract

The mechanical strength and dislocation velocities in single crystal Ge 1-x Si x alloys grown by the Czochralski method were investigated by compressive deformation and by the etch pit technique, respectively. In the temperature range 450-700°C and the stress range 3-20 MPa, the dislocation velocity in the GeSi with x = 0.004-0.022 decreases monotonically with an increase in the Si content, reaching about a half of that in Ge at x = 0.022, and can be expressed as a function of the stress and the temperature as expressed by the empirical equation known in other semiconductors. The yield stress of the GeSi alloy increases with increasing Si content from x = 0 to 0.4 and is temperature-insensitive at high temperatures, showing that the flow stress of alloy semiconductor has an athermal component which is absent in elemental or compound semiconductors. The hardening mechanism in alloy semiconductors is discussed.