| Summary: | 碩士 === 亞洲大學 === 資訊工程學系碩士班 === 101 === In the evolution of power industry, power devices with the property of high blocking capability but lower specific on-resistance are required in many applications of modern power electronics. Based on the extensive Superjunction (SJ) theory with stacked p and n columns in drift region, SJ devices have been recognized as advanced power devices that can meet the requirements. The main methods of realizing SJ devices are multi-epitaxy and deep trench technology. Unfortunately, the applications of SJ devices are commercially restricted by the complicated fabrication steps, charge imbalance and inter-diffusion problems.
In this work, Vertical Superjunction MOSFETs by sidewall doping technique is shown having high breakdown voltages more than 800 Volts with competitively low specific on resistance less than 15mΩ.cm2. It includes implantation of Arsenic at trench bottom. The method includes forming trench in the epitaxial layer of first conductivity. The dopants of second conductivity are then diffused into the epitaxial layer of first conductivity to provide a charge-balanced P-N junction of the first and second doped regions located along the trench depth. Finally, the trench is filled with oxide that helps to sustain the high breakdown voltage in the device. The performance in terms of specific on-resistance versus breakdown voltage of such a vertical super-junction device is noted to break the Silicon limit. Superjunction Termination is also developed with the same process.
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