Substrate orientation dependence on the solid phase epitaxial growth rate of Ge

Abstract

The solid phase epitaxial growth process has been studied at 330 C by transmission electron microscopy for Ge wafers polished at 10-15 increments from the [001] to [011] orientations. The velocity showed a strong dependence on substrate orientation with the [001] direction displaying a velocity 16 times greater than the [111] direction. A lattice kinetic Monte Carlo model was used to simulate solid phase epitaxial growth (SPEG) rates at different orientations, and simulations compared well with experimental results. Cross sectional transmission electron microscopy and plan view transmission electron microscopy revealed stacking fault and twin defect formation in the [111] orientation where all other orientations showed only hairpin dislocations. The twin defects formed from Ge SPEG were comparatively less dense than what has previously been reported for Si, which gave rise to higher normalized velocities and a constant [111] SPEG velocity for Ge. V

Atomistic modeling of Ge damage accumulation, amorphization and solid phase epitaxial regrowth

“…A recent study, Darby et al (2013) confirms past observations, Csepregi et al (1977) of strong dependencies on these orientations, mostly due to a strong contribution from twin defect formation during the recrystallization process, which slows down the recrystallization.…”

“…The presented model has been validated against the experimental results published by Darby et al (2013). Nevertheless, the model should also work for other measurements reported in the literature.…”

“…Considering the explanation given in Chapter 3, where an statistical mechanism in which two {111} twin planes engage into {011} microscopic configurations of recrystallization, this can be explained through the fact that (111)Ge regrown substrates present a less concentration of twin defects, Darby et al (2013) when compared to higher Si concentrations, Rechtin et al (1978) thus limiting this mechanism to occur.…”

“…Darby et al (2013 The experimental first 30 minutes (∼50 nm, depending on the configuration) measured correspond to a planarization process which is not taken into consideration for the results Darby et al (2013). Such process could be simulated for other less computationally expensive conditions, and will be more deeply discussed in Section 6.4.2.…”

The demonstration of a D-SMT stressor on Ge planer n-MOSFETs

“…8 Recent studies have examined the characteristics of crystal re-growth velocity in the un-stressed bulk Ge. 9 However, the characteristics of crystal re-growth velocity in the stressed Ge with the application of the stressed SiN capping film are still unclear, and no studies have been published for the Ge planer Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) implemented with the D-SMT stressor. This work demonstrates the huge device performance improvement by using a D-SMT stressor in a Ge planer device, based on an investigation of the characteristics of crystal re-growth velocities along different directions in the stressed Ge.…”