Three different processes taking place in a plasma reactor; namely, heating and melting of plasma-born hydrogenated silicon clusters by reactions with atomic hydrogen, hydrogen-induced healing of cluster-damaged silicon surfaces, and cluster-catalyzed epitaxial growth of thin silicon films have been investigated by means of molecular dynamics simulations. Two plasma-born hydrogenated silicon clusters representing amorphous and crystalline structures are chosen to be exposed to atomic hydrogen as in a realistic plasma reactor. We investigate quantitatively how the clusters heat up and melt by the subsequent reactions with H-atoms. A silicon surface which was partly damaged by a too violent cluster impact has been treated by hydrogen atoms. We have observed that the ill-defined silicon surface is rearranged to its initial crystalline structure after the exposure with atomic hydrogen if the appropriate H-atom flux is chosen; i.e., due to the surface reaction dynamics with hydrogen atoms, the silicon atoms of the investigated hydrogenated silicon cluster are positioned in an epitaxial surface structure. We have performed an in-depth study of the deposition dynamics of hydrogenated silicon clusters on a crystalline silicon substrate by controlling the parameters governing the cluster surface deposition. We have found that epitaxial growth of thin silicon films can be obtained from cluster deposition if the impact energies are sufficiently high for cluster atoms and surface atoms touching the cluster to undergo a phase transition to the liquid state before being recrystallized in an epitaxial order. Yet more strikingly, by applying a non-normal incidence angle for the impinging clusters, the epitaxial growth efficiency could considerably be enhanced. Those findings are crucially important to improve the high-speed growth of epitaxial silicon thin films at low temperatures using Plasma-Enhanced Chemical Vapor Deposition (PECVD) techniques for industrial applications.
Authors
- Bibliographic Reference
- Ha-Linh Thi Le. Molecular dynamics simulations of H-induced plasma processes and cluster-catalyzed epitaxial growth of thin silicon films. Computational Physics [physics.comp-ph]. Ecole Polytechnique X, 2014. English. ⟨NNT : ⟩. ⟨pastel-00985657⟩
- HAL Collection
- ['Ecole Polytechnique', 'PASTEL - ParisTech', 'ParisTech', 'CNRS - Centre national de la recherche scientifique', 'Laboratoire de Physique des Interfaces et des Couches Minces (PICM)', 'Polytechnique', 'Département de physique', 'Laboratoire de physique des interfaces et des couches minces']
- HAL Identifier
- 985657
- Institution
- École polytechnique
- Laboratory
- Laboratoire de physique des interfaces et des couches minces [Palaiseau]
- Published in
- France
Table of Contents
- Contents 7
- List of Figures 9
- List of Tables 13
- 1 Introduction 14
- 2 Computational methodology 19
- 2.1 Molecular dynamics simulations 19
- 2.1.1 Classical molecular dynamics simulation 19
- 2.1.1.1 Basic of molecular dynamics simulation 19
- 2.1.1.2 MD simulation procedure 20
- 2.1.1.3 Empirical interatomic Ohira-Tersoff potential 23
- 2.1.2 Ab initio molecular dynamics simulation 26
- 2.1.2.1 Why ab initio molecular dynamics? 26
- 2.1.2.2 Adiabatic and Born-Oppenheimer approximations 27
- 2.1.2.3 Kohn-Sham density functional theory 29
- 2.1.2.4 Born-Oppenheimer molecular dynamics 31
- 2.1.2.5 Ab initio forces: the Hellmann-Feynman theorem 32
- 2.2 Methods to “measure” system properties 33
- 2.2.1 Cluster temperature 33
- 2.2.2 Radial distribution function 34
- 2.2.3 Mean-square displacement 35
- 3 Heating and melting of plasma-born hydrogenated silicon clusters by reactions with atomic hydrogen 36
- 3.1 Introduction 36
- 3.2 Computational details 38
- 3.3 Results and Discussions 39
- 3.3.1 Hydrogen-induced heating of hydrogenated silicon nanoparticles 39
- 3.3.1.1 Si15H10+nH 39
- 3.3.1.2 Si29H24+nH 40
- 3.3.2 Melting dynamics 41
- 3.4 Conclusions 46
- 4 Hydrogen-induced healing of cluster-damaged silicon surfaces 48
- 4.1 Introduction 48
- 4.2 Simulation details 50
- 4.2.1 Deposition of plasma-born hydrogenated silicon clusters on H-terminated Si(100)-(2x1) surfaces 50
- 4.2.2 Hydrogen treatment processes 52
- 4.3 Results 53
- 4.4 Conclusions 58
- 5 Cluster-catalyzed epitaxial growth of thin silicon films 59
- 5.1 Introduction 59
- 5.2 Simulation details 63
- 5.3 Results 64
- 5.3.1 Deposition of Si15H10 clusters on a H-terminated Si(100)-(2x1) surface 64
- 5.3.2 Deposition of Si8H12 clusters on H-terminated Si(100)-(2x1) surfaces 69
- 5.3.3 Deposition of Si28H13 clusters on H-terminated Si(100)-(2x1) surfaces 76
- 5.3.4 Deposition of Si29H24 clusters on H-terminated Si(100)-(2x1) surfaces 80
- 5.4 Conclusions 87
- 6 Conclusions and Perspectives 90
