Formation and preferred growth behavior of grooved seed silicon substrate for kerfless technology*

Abstract

Kerfless technology is a promising alternative for reducing cost and providing flexible thin crystals in silicon-based semiconductors. In this work we propose a protruded seed substrate technology to prepare flexible monocrystalline Si thin film economically. Grooved seed substrate is fabricated by using SiN x thin film as a mask for the wet-etching and thermal oxidation process. After the SiN x layer on the wedged strip is removed by hot phosphoric acid, the pre-defined structured substrate is achieved with the top of the strip serving as the seed site where there is no oxide layer. And a preferred growth of epitaxial Si on the substrate is performed by introducing an intermittent feed method for silicon source gas. The technique in this paper obviously enhances the mechanical stability of the seed structure and the growth behavior on the seed sites, compared with our previous techniques, so this technique promises to be used in the industrial fabrication of flexible Si-based devices.

Weak Stefan Formulation for Bulk Crystal Growth with Non-smooth Interfaces

“…Weinstein et al [9] applied a Lattice Boltzmann model to track interface evolution while accounting for anisotropic interface attachment kinetics. Other approaches that track the interface evolution implicitly, like phase field models, are also used to model crystal growth [10]. However, they are better suited to model phase transition at the microscopic level based on thermodynamic considerations, like dendrite growth and phase boundaries [11,12].…”

“…The assumption on the smoothness of the interface puts a restriction on the applicability of the classical Stefan formulation. This is especially relevant for crystal growth systems since the occurrence of non-smooth interfaces is routine [10,13,14]. Figure 1 provides two example of frequently encountered situations in crystal growth where the classical Stefan formulation is not applicable.…”