Ge-Sb phase-change film was deposited into a trenched structure with trenches 40 nm in diameter by means of atomic vapor deposition, and the trench-covering ability of the film was determined under various conditions. Three different plasma conditions were created in the reaction chamber-non-plasma, semi-shielded plasma, and direct plasma-by inserting or removing a metal grid in the middle of the reaction chamber. In addition, film composition was varied among Ge, Ge-Sb, and Sb. Partial pressure and time of flight of precursor molecules in the reaction chamber were varied by controlling precursor feeding time and precursor injection position, respectively. The origin of the trench-covering ability of the films was analyzed by applying the concept of an effective sticking coefficient.

Keywords: Phase change materials; Trench-covering ability; Atomic vapor deposition; Multi-scale modeling; Effective sticking coefficient