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Title: Thermodynamics and kinetic behaviors of thickness-dependent crystallization in high-k thin films deposited by atomic layer deposition

Atomic layer deposition is adopted to prepare HfO{sub 2} and Al{sub 2}O{sub 3} high-k thin films. The HfO{sub 2} thin films are amorphous at the initial growth stage, but become crystallized when the film thickness (h) exceeds a critical value (h{sub critical}{sup *}). This phase transition from amorphous to crystalline is enhanced at higher temperatures and is discussed, taking into account the effect of kinetic energy. At lower temperatures, the amorphous state can be maintained even when h>h{sub critical}{sup *} owing to the small number of activated atoms. However, the number of activated atoms increases with the temperature, allowing crystallization to occur even in films with smaller thickness. The Al{sub 2}O{sub 3} thin films, on the other hand, maintain their amorphous state independent of the film thickness and temperature owing to the limited number of activated atoms. A thermodynamic model is proposed to describe the thickness-dependent phase transition.
Authors:
; ;  [1] ;  [2]
  1. State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China)
  2. State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, People's Republic of China and Department of Physics and Opt-electronic Engineering, Xi'an University of Arts and Science, Xi'an, Shaanxi 710049 (China)
Publication Date:
OSTI Identifier:
22392113
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 33; Journal Issue: 1; Other Information: (c) 2014 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 42 ENGINEERING; ALUMINIUM OXIDES; AMORPHOUS STATE; CRYSTAL GROWTH; CRYSTALLIZATION; DEPOSITS; HAFNIUM OXIDES; KINETIC ENERGY; THERMODYNAMIC MODEL; THERMODYNAMICS; THICKNESS; THIN FILMS