High-Voltage Isolated Square Waveform Converter with DC-Offset Voltage for Physical Vapor Deposition (PVD) Applications

This paper proposes two isolated asymmetric rectangular waveform converters for high voltage pulse voltage generation from 100 V to -2 kV in surface coating by the physical vapor deposition (PVD) method. The PVD method is a surface coating method using chemical reactions of materials such as argon gas. The surface shape of the target sample is regulated by the external square waveform converter, which requires the capability of variable duty control and variable amplitude operation in order to manage the coating performance. This paper presents details of a circuit configuration that enables variable duty control from 0 - 100% and variable amplitude operation to 100 V. Furthermore, the load model in the PVD method is also shown to clarify the behavior of the square waveform converter. The experimental results show that the switching duty is variable by 50%, 20% and 80% with the positive voltage amplitude adjusted by 25% of the peak voltage.