Study On Composite Pulse Magnetron Suptterring Discharge Characteristic And Numerical Simulation

High Power Impluse Magenetron Sputtering(Hi PIMS) is a widely used coating technology, featuring high ionization rate, instantaneous high power density and high-quality coatings, and draws attention from both academic and industrial fields in recent decades. However, due to its low average power, coating deposition rates are relatively low, which restricts its industrial applications.To improve coating deposition rates of Hi PIMS, a novel composite pulse magnetron sputtering technology is presented by coupling two independent pulses. The higher and shorter pulse is utilized to ionize gas, and the lower and longer pulse is designed to preserve discharge. Consequently, high density plasma is gained without average power decrease.Based on Particle-in-Cell/Monte Carlo model, magnetron sputtering supplying by composite pulse power was simulated numerically. Plasma kinetics and discharge current waveform forming mechanism during discharge process are investigated. The results show that plasma distribution was determined by the combinational effect of electrical and magnetron field, and the plasma distribution affected electrical potential distribution conversely. During magnetron sputtering discharge process, spatial potential rises continuously. Cathode sheath with high potential gradient and ionization area with high density plasma have formed. As voltage on target improves, gas ionization rate increases, ion energy rises, and current density on target rises. As for composite pulse, spatial potential and plasma density distributions are similar with ones under work pulse. After the cut-off of ignition pulse, work pulse preserves high density plasma and current density effectively, but spatial ion energy drops as voltage decreases..Using FPGA as central processing unit, touch screen as user interface, composite pulse power supply was developed. Parameter of each pulse can be adjusted independently, including voltage, pulse width and frequency, and phase difference can be set feasibly as well. To protect from damage by arcing, power supply is armed with automatically reducing voltage function. Power supply features feasible settings and user-friendly interface.Power supply was tested with water load. Realization of various waveforms was verified by setting different pulse parameter and monitoring output of voltage and current. The results shows, current is linear proportional to voltage with water load. Power supply was tested on Cr target under the condition of vacuum. Different from water load, resistance character of plasma is not linear, leading to a more complex current waveform. As waveform of voltage is rectangle, waveform of current is closed to triangle or fan-shaped. As for composite pulse, current soars during ignition pulse. Current peak is highly related to voltage and pulse width. Current drops on the cut-off of ignition pulse, and the dropping rate depends on the voltage of work pulse. The result shows, under composite pulse mode, higher current peak was gained by ignition stage, and discharge current was preserved at work pulse stage. Therefore, average current was improved significantly.