Nanoscale Thermal Property of Amorphous SiC: A Molecular Dynamics Study
- PDF / 485,123 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 45 Downloads / 232 Views
1022-II05-10
Nanoscale Thermal Property of Amorphous SiC: A Molecular Dynamics Study Weiqiang Wang, Rajiv K. Kalia, Aiichiro Nakano, and Priya Vashishta Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA, 90089
ABSTRACT Thermal properties of amorphous silicon carbide (a-SiC) at nanometric scales are studied by molecular dynamics (MD) simulations based on an empirical interatomic potential. A scalable parallel MD algorithm is used for studying systems as long as 30nm. To validate the potential, phonon density of states and specific heat of a-SiC are first calculated. Size effects are studied, and errors are estimated for the temperature profile for different system sizes. Simulation time required to achieve steady temperature profiles is also determined. Finally the thermal conductivities of a-SiC at various temperatures are calculated. The results show that thermal conductivities of a-SiC at nanometric scale also agree with Slackís minimum thermal conductivity model. INTRODUCTION Rapid growth in the engineering of smaller and smaller semiconductor devices has attracted many scientistsí attention to study the material properties at the nanometer scale. Among all the semiconductor materials, silicon carbide (SiC) is one of the most prominent compounds due to its excellent semiconducting and mechanical properties at high temperatures. However, the high-level deposition requirement of SiC layers makes the choice of amorphous SiC (a-SiC) more attractive, which also preserves most of the favorable properties of crystalline SiC. [1,2] Meanwhile, thermal properties of a-SiC at the nanometer scale are of great interest to scientists, because the thermal management at nanometer scale is important for the performance of devices and the thermal transport properties at this small scale could be changed dramatically due to the strong size confinement [3]. Atomistic simulations are considered an appropriate approach of studying thermal conductivity at this small scale. Application of this method does not need a sophisticated understanding of the fundamental heat transport process of a particular material. With an appropriate interatomic potential, interesting physical properties can then be generated naturally through simply evolving the system by Newtonís equations of motion. In past years, we have successfully studied structural transformation of crystalline SiC [4], structural correlations in amorphous SiC, and indentation of crystalline [5], amorphous [6] and nanophase SiC [7] with our empirical potential, which includes effects of steric repulsion, charge transfer between atoms, charge-dipole interactions and van der Waals interaction in its two-body term and effects of covalent in its three-body term. In this work, we will focus on the study of thermal dynamic properties, i.e., the thermal conductivity of amorphous SiC with our potential by the non-equilibrium molecular dynamics (NEMD) method [8].
In the following section, we introduce the interatomic potential used t
Data Loading...
