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SSL Seminar Series 2001 No. 3
Title: Reaction Mechanism of Si3N4 Plasma Enhanced Chemical
Vapour Deposition and Its Mechanism
Speaker: Mr. Yang Shuowang
Date: 2nd February 2001, Friday
Time: 5:00-6:00pm
Venue: Physics Resource Room S13, 02-16
Abstract
Approximately 40% of the steps in the fabrication of microelectronics
use plasma processes. One process which has been investigated extensively
and applied widely over the last decade is plasma enhanced Chemical
Vapour Deposition (PECVD).
Silicon nitride, Si3N4, thin film deposited by plasma-enhanced CVD
has been studied for over two decades and is widely used in the semiconductor
industry as a passivating coating, a diffusion barrier, and more recently
as a gate dielectric and inter-level metal isolation in amorphous
Si thin film circuitry. Silicon nitride can also be deposited by thermal
CVD, but plasma enhanced CVD allows process carried out at much low
temperature which are compatible with more of the steps in semiconductor
manufacturing processes. However, PECVD film is not general stoichiometric
Si3N4 and is more properly described as SixNyHz. In real case of manufacturing
process, PECVD is extraordinarily complex and deposition characteristics
depend strongly on gas pressure, flow rate, RF power and frequency,
reactor geometry and substrate temperature. The process is high technical
containing and high cost consuming. Therefore, computer modelling
of PECVD is always a will of both for industrial engineers and researchers.
So fundamental understanding of plasma processes is required in simulation
work.
Currently there are two approaches of method in PECVD modelling, Monte
Carlo statistical and molecular dynamic approach. In current work,
molecular dynamic approach is the major tool assisted with ab initio
or semi-empirical quantum chemistry. The plasma and a surface CVD
chemistry mechanism of Si3N4 are proposed by several hundreds of chemical
reactions described with respective thermodynamic and kinetic parameters.
Some popular software such as ChemKin, Gaussian 98 and F*A*C*T were
used in this work. The simulation results well agree with the experimental
data.
PROFILE OF PRESENTER
Mr. Yang Shuowang obtained his first degree in physical chemistry
in 1985 from Zhejiang University and three years later he obtained
his Master degree in the field of inorganic chemistry from the same
university. His second master degree is in organic and nature products
chemistry from National University of Singapore in 1996. Currently
he is a senior research engineer in Institute of High Performance
Computing. |
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