69th Annual Gaseous Electronics Conference
Volume 61, Number 9
Monday–Friday, October 10–14, 2016;
Bochum, Germany
Session QR2: Plasma Surface Interaction
8:30 AM–10:30 AM,
Thursday, October 13, 2016
Room: 2a
Chair: Peter Ventzek, Tokyo Electron
Abstract ID: BAPS.2016.GEC.QR2.1
Abstract: QR2.00001 : Hybrid molecular dynamics simulation for plasma induced damage analysis
8:30 AM–9:00 AM
Preview Abstract
Abstract
Author:
Masaaki Matsukuma
(Tokyo Electron Limited)
In order to enable further device size reduction (also known as Moore's law)
and improved power performance, the semiconductor industry is introducing
new materials and device structures into the semiconductor fabrication
process. Materials now include III-V compounds, germanium, cobalt,
ruthenium, hafnium, and others. The device structure in both memory and
logic has been evolving from planar to three dimensional (3D). One such
device is the FinFET, where the transistor gate is a vertical fin made
either of silicon, silicon-germanium or germanium. These changes have
brought renewed interests in the structural damages caused by energetic ion
bombardment of the fin sidewalls which are exposed to the ion flux from the
plasma during the fin-strip off step. Better control of the physical damage
of the 3D devices requires a better understanding of the damage formation
mechanisms on such new materials and structures. In this study, the damage
formation processes by ion bombardment have been simulated for Si and Ge
substrate by Quantum Mechanics/Molecular Mechanics (QM/MM) hybrid
simulations and compared to the results from the classical molecular
dynamics (MD) simulations. In our QM/MM simulations, the highly reactive
region in which the structural damage is created is simulated with the
Density Functional based Tight Binding (DFTB) method and the region remote
from the primary region is simulated using classical MD with the
Stillinger-Weber and Moliere potentials. The learn on the fly method is also
used to reduce the computational load. Hence our QM/MM simulation is much
faster than the full QC-MD simulations and the original QM/MM simulations.
The amorphous layers profile simulated with QM/MM have obvious differences
in their thickness for silicon and germanium substrate. The profile of
damaged structure in the germanium substrate is characterized by a deeper
tail then in silicon. These traits are also observed in the results from the
mass selected ion beam experiments. This observed damage profile dependence
on species and substrate cannot be reproduced using classical MD
simulations. While the Moliere potential is convenient to describe the
interactions between halogens and other atoms, more accurate interatomic
modeling such as DFTB method which takes the molecular orbitals into account
should be utilized to make the simulations more realistic. Based on the
simulations results, the damage formation scenario will be discussed.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2016.GEC.QR2.1