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<專題討論>2020/4/30(四)14:10綜合大樓2樓48218教室演講 : 柳克強 教授(清華大學工程與系統科學系)

張貼者:2020年4月26日 下午8:28Dabby Lu
講題: Low temperature plasmas – Characterizations and Applications
摘要: Low temperature plasmas have a wide range of applications, including micro/nano fabrication, lighting/displays, and even bio-medical treatments.  In this talk, an overview of fundamentals of low temperature plasmas will first be given.  In the second part of this talk, results from our recent efforts on fluid model simulations analysis and microwave based diagnostics will be highlighted.  The numerical simulations were conducted by using a commercial code – COMSOL Multi-physics.  The first reactor studied is a microwave plasma discharge operated at the TM023 cavity mode.  Simulation results show that a hot plasma ball located above the grounded stage can be sustained by microwave power propagating along the stage surface in a surface wave type mode.  Simulation analysis has also been conducted for ferromagnetic enhanced inductively coupled plasmas (FMICP).  As a results of a structure consisting of a metallic enclosure and a DC-block, simulation results reveal a discharge mode transition from capacitive to inductive coupling, an important physical mechanism for the ignition and sustaining of the FMICP discharges.  For the microwave based diagnostics, two types of sensors have been investigated.  The first one is based on a transmission line and is operated as an interferometer.  The density is determined by the phase shift of a microwave going through the transmission line as the plasma density is varied.  Several transmission line structures have been studied, including a coaxial line, a ridged microstrip line and an air-bridge microstrip line.  Numerical Simulation analysis and experimental results show that the air-bridge structure yields the highest sensitive for plasma density measurements.  The second type of device is a probe employing a microwave resonant structure where the resonant frequency is also affected by the plasma density.   Characteristics of several resonant type microwave plasma density sensors being developed will also be presented.  
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Dabby Lu,
2020年4月26日 下午8:28
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