KINETICS OF SOLID-PHASE EPITAXIAL REGROWTH IN AMORPHIZED SI0.88GE0.12 MEASURED BY TIME-RESOLVED REFLECTIVITY

Time-resolved reflectivity has been used to measure the rate of solid phase epitaxial regrowth (SPER) in situ during annealing of strained Si0.88Ge0.12 epilayers on Si preamorphized by the implantation of Si. The SPER velocities were measured over more than two orders of magnitude at temperatures from 503 to 603-degrees-C. The results confirm that the average SPER velocity in thin, strained Si0.88Ge0.12 layers is less than that in pure Si. Furthermore, these real-time measurements demonstrate that the SPER rate for strained Si0.88Ge0.12 alloys is not a constant during regrowth at a fixed temperature but varies systematically as a function of the position of the amorphous-crystalline interface. The activation energy barrier of SPER in strained Si0.88Ge0.12 is higher than that in pure Si and is also a function of interface position, ranging from 2.94 to 3.11 eV. Cross-section transmission electron microscopy shows that strain-relieving defects are introduced coincidentally with the minimum regrowth rate.