Modeling solid phase epitaxial growth for patterned Ge substrates

Modeling the two-dimensional (2D) solid phase epitaxial growth (SPEG) of amorphized Ge has become important due to the renewed interest in Ge as an alternative material to Si in complementary metal-oxide-semiconductor (CMOS) devices. In this work, a 2D SPEG model that uses level set techniques as implemented in the Florida object oriented process simulator (FLOOPS) to propagate regrowth fronts with variable crystallographic orientation patterned material is presented. Apart from the inherent orientation dependence of the SPEG velocity, it is established that nitride-induced stress can affect mask edge defect formation for patterned samples. Data acquired from transmission electron microscopy (TEM) experiments matches well with simulations, thus providing a stable model for simulating 2D regrowth and mask edge defect formation in Ge. In comparison to Si, mask edge defect formation is less apparent in Ge due to a more isotropic orientation dependence for Ge SPEG.