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DC Discharge Studies Using PIC-MCC
| Content Provider | Semantic Scholar |
|---|---|
| Author | Hammel, Jeffrey P. Verboncoeur, John P. |
| Copyright Year | 2003 |
| Abstract | DC discharges, both magnetized and unmagnetized, are used in plasma processing for sputtering film deposition, ion implantation, and other processes. The objective of this study is to compare theoretical analysis of a DC discharge with results obtained using the particle in cell with Monte Carlo collisions (PIC-MCC) method. PIC-MCC is used to accurately model kinetic processes present in DC discharges, including charged particle collisions with homogeneous Maxwellian neutral molecules. Parameters of interest to materials processing, such as the ion energy and angular distribution at the cathode, may be obtianed using PIC. Cross-validation of PIC-MCC simulation and analysis may be used to improved both computational and analytic models. Suggestions for the improvement of basic theory are presented. DC discharges of interest in this study are azimuthally symmetric unmagnetized discharges. A cylindrical insulating tube is bound on the ends by electrodes. A DC power source is used to drive the discharge. A dielectric wall contains the plasma in the radial direction. Argon and helium were used as feedstock gases. In laboratory DC discharges, gas breakdown is seen at a critical voltage as a function of the distance between the plates and gas pressure. After a transient period, a steady state density and cathode fall distance are observed. If the transient behavior is not of interest, it is more practical for the PIC-MCC method to start with a density profile reasonably close to steady state. Radial DC discharges, both magnetized and unmagnetized, were also studied. In this configuration, the plasma is confined between a cathode at r = r1 and an anode at r = r2, where r2 > r1. Periodic and dielectric boundary conditions were used for the ±ẑ-normal boundaries. These configuations resemble cylindrical discharges as used for plasma processing. Several DC discharges are simulated with PIC and the results compared with theory. Both 1d-3v and 2d-3v models are simulated. Two dimensional effects are discussed. Possible reasons for differences between the PIC and theoretical model are discussed and suggestions are made for the improvement of the theory to more accurately compare to the kinetic results and overcome previous assumptions of the model. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://langmuir.eecs.berkeley.edu/~jhammel/report.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
