Theoretical study of discrete particle effect in a nano-scale trench and Development of a kinetic simulation technique for a large area capacitively coupled plasma source

Abstract

The topic is in two subjects. The first subject is a theoretical study of the discrete particle effect in a nano-scale trench and the second subject is on a large area capacitively coupled plasma source for LCD processing. Understanding the charging process in a nano trench is an important task for the nano fabrication. In this thesis, strong coulomb interactions between discrete particles are studied. Our study has been motivated by the fact that the discrete charges in an extremely small size trench interact strongly with each other, hence the conventional Debye shileding assumption break down and the charged particles experience strongly spatiotemporal potential fluctuation during their flights. In a strongly coupled charged system, a simplified technique of coulomb summation for infinitely periodic systems are briefly reviewed and explained. We then introduce new phenomena during a charging process in a nano trench : charging potential fluctuation due to strong coulomb interaction without Debye shielding. In the first part of the subject, physics model and simulation method are shown. A simplified two-dimensional Monte Carlo simulation is performed to investigate the electric field fluctuations caused by strong Coulomb interactions between discrete particles in nanometer scale trenches. It is found that the discrete particle effect should be an important part of the nano-scale trench physics, raising the ion orbit scatterings in the trench, enhancing the ion deposition on the side walls, and dispersing the material contact energy of the incidence ions. In the second topic, simulation of a large area capacitively coupled plasma requires large scale computational resource. It requires many particles and grids for the electric field calculation at an acceptable level. A high efficiency parallelized simulation code is inevitable both for particle push and field calculation. For this purpose the particle-in-cell/Monte Carl...