Chemical Vapor Deposition of Elemental Crystallogen Thin Films

Abstract

A consolidation of the fundamentals of elemental crystallogen chemical vapor deposition (CVD) is a necessity in view of the extensive evidence accumulated over the last few decades. An in-depth understanding of deposition mechanisms via hydrides asks for a discerning understanding of molecular hydrogen dissociative adsorption, precursor thermal decomposition, and CVD growth rates. With those, a groundbreaking paradigm shift comes to light. GR activation energy E(GR) fingerprints the surface energy. SE ≈ 2 × E(GR)/(a×a), where SE is surface energy, E(GR) activation energy, a lattice parameter. Hydride precursor thermal decomposition consistency with the corresponding solid growth kinetics is demonstrated. Heterogeneous TD kinetics captures a solid deposition and not a gas phase molecular reaction. Thermodynamic equilibrium is achieved during the heterogeneous thermal decomposition of silicon precursors. The popular split between mass-transfer and kinetic regimes is not supported by evidence. Three mechanisms are apparent. The first is controlled by a Si–H bond dissociation energy. The second is controlled by an H–H bond dissociation energy. The last is controlled by a Si–Si bond dissociation energy as lattice sites are sealed off with Si–H bonds.