Computer Simulation Of Magnetron Sputtering Of Thin Film Growth

Since invented in early 1970s,magnetron sputtering has become one of the most widely used methods of thin film preparation.Due to its relatively high deposition rate and film quality,it has been successfully applied in numerous fields such as integrated circuit process,specific functional coating materials and material modification.However,up to now,the control of magnetron sputtering thin film deposition process still depends on experimental experience.Therefore, it is of great practical values to comprehensively investigate the effects of various technical factors.As the rapid evolvement of computer technologies;computational physics method has grown into one of the most crucial methods in scientific researches. Abundant studies on the essential mechanism of thin film growth were successfully conducted and varieties of algorithms were developed to simulate the separated physical processes related to thin film growth.However,the sputtering process spans a wide range in time and space scales,such a multi-scale problem brings challenges to numerical simulation techniques.In this thesis,a comprehensive analysis of the complete process of magnetron sputtering thin film deposition is carried out using the proposed multi-scale model.The generation,transport and deposition of sputtered atoms and the thin film initial stage growth progress,thin film macro-topography are modeled by the multi-scale model including Monte Carlo(MC) method, Molecular Dynamics(MD) method,Particle-in-cell(PIC) method,Embedded Atom Method(EAM),and Clouds-in-Cells(CIC) method.In addition,the effects of substrate temperature,deposition rate,magnetic-field distribution, magnetic-field intensity,minus bias of the target,pressure of the chamber and target-substrate distance on the physical properties of thin film are studied.The simulation results indicate that,the minus bias of the target apparently affect on the time for the system to reach the "quasi-steady state" and together with the energy of both ions and electrons.If the minus bias is increased from 300V to 700V,the time is shortened with one order of magnitude.Meanwhile,the average energy of ions and electrons is two times as it was when the bias was 300V.Secondly,the ion current density graph shows that the curve of the "flat" type magnetic field distribution has the lowest and widest peak. Correspondingly,the etching profile under "flat" magnetic field distribution is the shallowest and widest,which implies the highest target utilization rate. Thirdly,the collision times increases with the increasing of the pressure of the chamber and the distance between target and substrate.Finally,during the initial stage of the deposition process,the relative density of thin film increases with the increase of substrate temperature or the decrease of deposition rate.Moreover, the thin film becomes smoother as target-substrate distance increases.