Layer-by-Layer Growth of GeSbTe Thin Films by Metal-Organic CVD for Phase Change Memory Applications

Abstract

Ge, GeTe, and GeSbTe (GST) films are grown on both planar TiAlN/Si substrates and a trench structure (diameter 120 mu; depth 200 nm) using layer-by-layer, metal-organic (MO) CVD. The GeTe and GeSbTe films completely fill the trench structure, and show well-crystallized phases with a rhombohedral and hexagonal structure, respectively. The GeTe films grown on the trench structure exhibit stoichiometric variations along the depth of the trench. Stoichiometric Ge(2)Sb(2)Te(5) Compositions are observed only at the center of the trench structure. The concept of layer-by-layer MOCVD could be applied for depositing GST and GeTe films from constituent precursors with large differences in decomposition temperatures, provided the composition variation can be overcome.