针对如何产生均匀和稳定的超声速非平衡等离子体这一科学问题,为进一步探究超声速气流电容耦合射频放电特性,建立了超声速非平衡电离磁流体动力技术实验系统,开展了Ma=3.4条件下,超声速气流边界层与主流中心区的电容耦合射频放电特性研...针对如何产生均匀和稳定的超声速非平衡等离子体这一科学问题,为进一步探究超声速气流电容耦合射频放电特性,建立了超声速非平衡电离磁流体动力技术实验系统,开展了Ma=3.4条件下,超声速气流边界层与主流中心区的电容耦合射频放电特性研究;同时针对超声速放电等离子体的实时诊断问题,基于均匀射频放电模型,联立能量平衡方程,建立等离子体诊断模型对平均电子数密度与电子温度等参数进行诊断。结果表明:超声速气流条件下,通过电容耦合射频可以产生均匀和稳定的放电等离子体;分子数密度是影响超声速气流放电特性的主要因素,同时超声速气流对平均电子温度的影响很小,约为0.46 e V。展开更多
Local measurement of plasma radial uniformity was performed in a dual frequency capacitively coupled argon plasma （DF-CCP） reactor using an optical probe. The optical probe collects the light emission from a small s...Local measurement of plasma radial uniformity was performed in a dual frequency capacitively coupled argon plasma （DF-CCP） reactor using an optical probe. The optical probe collects the light emission from a small separate volume in plasma, thus enabling to diagnose the plasma uniformity for different experimental parameters. Both the gas pressure and the low- frequency （LF） power have apparent effects on the radial uniformity of argon plasma. With the increase in either pressure or LF power, the emission profiles changed from a bell-shaped to a double-peak distribution. The influence of a fused-silica ring around the electrodes on the plasma uniformity was also studied using the optical probe. Possible reasons that result in nonuniform plasmas in our experiments are discussed.展开更多
A novel technique to generate high-density plasma-called inductively coupled plasma （ICP）, enhanced capacitively coupled plasma （CCP）- is successfully developed. The plasma can be generated using different frequen...A novel technique to generate high-density plasma-called inductively coupled plasma （ICP）, enhanced capacitively coupled plasma （CCP）- is successfully developed. The plasma can be generated using different frequency configurations, such as ICP-enhanced single-frequency ca- pacitively coupled plasma （SFCCP） and dual-frequency capacitively coupled plasma （DFCCP）. The characteristics of the plasma in the following frequency combinations are mainly investigated using a Langmuir probe, SFCCP （60 MHz）, DFCCP （60 MHz, 13.56 MHz）, SFCCP （60 MHz） and inductively coupled plasma （13.56 MHz）, DFCCP （60 MHz, 13.56 MHz） and inductively coupled plasma （13.56 MHz）. In this letter, the nitrogen and hydrogen mixture gas discharge charac- teristics of different configurations are studied. After the analysis, we can acquire the electron temperature and ion density. Then, the effect of inductively coupled discharge on SFCCP and DFCCP can be summarized. In our preliminary investigations, the main results can be given as follows. ICP can make the density of SFCCP increase and the distribution of the electron temper- ature in a radial direction more uniform. In addition, ICP not only can make the ion density of DFCCP increase, but also can improve the radial uniformity. F^rther experiments may be needed to clarify the mechanism.展开更多
The capacitively coupled plasma in the gaseous electronics conference reference reactor is numerically investigated for argon flow using a non-equilibrium plasma fluid model. The finite rate chemistry is adopted for t...The capacitively coupled plasma in the gaseous electronics conference reference reactor is numerically investigated for argon flow using a non-equilibrium plasma fluid model. The finite rate chemistry is adopted for the chemical non-equilibrium among species including neutral metastable, whereas a two-temperature model is employed to resolve the thermal non-equilibrium between electrons and heavy species. The predicted plasma den- sity agrees very well with experimental data for the validation case. A strong thermal non-equilibrium is observed between heavy particles and electrons due to its low collision frequency, where the heavy species remains near ambient temperature for low pressure and low voltage conditions （0. t Torr, 100 V）. The effects of the operating parameters on the ion flux are also investigated, including the electrode voltage, chamber pressure, and gas flow rate. It is found that the ion flux can be increased by either elevating the electrode voltage or lowering the gas pressure展开更多
文摘针对如何产生均匀和稳定的超声速非平衡等离子体这一科学问题,为进一步探究超声速气流电容耦合射频放电特性,建立了超声速非平衡电离磁流体动力技术实验系统,开展了Ma=3.4条件下,超声速气流边界层与主流中心区的电容耦合射频放电特性研究;同时针对超声速放电等离子体的实时诊断问题,基于均匀射频放电模型,联立能量平衡方程,建立等离子体诊断模型对平均电子数密度与电子温度等参数进行诊断。结果表明:超声速气流条件下,通过电容耦合射频可以产生均匀和稳定的放电等离子体;分子数密度是影响超声速气流放电特性的主要因素,同时超声速气流对平均电子温度的影响很小,约为0.46 e V。
基金supported by National Natural Science Foundation of China (Nos. 10635010, 10975029)Beijing Key Laboratory of Printing & Packaging Materials and Technology of Beijing Institute of Graphic Communication of China (No. KF201004)
文摘Local measurement of plasma radial uniformity was performed in a dual frequency capacitively coupled argon plasma （DF-CCP） reactor using an optical probe. The optical probe collects the light emission from a small separate volume in plasma, thus enabling to diagnose the plasma uniformity for different experimental parameters. Both the gas pressure and the low- frequency （LF） power have apparent effects on the radial uniformity of argon plasma. With the increase in either pressure or LF power, the emission profiles changed from a bell-shaped to a double-peak distribution. The influence of a fused-silica ring around the electrodes on the plasma uniformity was also studied using the optical probe. Possible reasons that result in nonuniform plasmas in our experiments are discussed.
基金supported by National Natural Science Foundation of China(Nos.11075114,10975106)the Priority Academic Program Development of Jiangsu Higher Education Institutions of China
文摘A novel technique to generate high-density plasma-called inductively coupled plasma （ICP）, enhanced capacitively coupled plasma （CCP）- is successfully developed. The plasma can be generated using different frequency configurations, such as ICP-enhanced single-frequency ca- pacitively coupled plasma （SFCCP） and dual-frequency capacitively coupled plasma （DFCCP）. The characteristics of the plasma in the following frequency combinations are mainly investigated using a Langmuir probe, SFCCP （60 MHz）, DFCCP （60 MHz, 13.56 MHz）, SFCCP （60 MHz） and inductively coupled plasma （13.56 MHz）, DFCCP （60 MHz, 13.56 MHz） and inductively coupled plasma （13.56 MHz）. In this letter, the nitrogen and hydrogen mixture gas discharge charac- teristics of different configurations are studied. After the analysis, we can acquire the electron temperature and ion density. Then, the effect of inductively coupled discharge on SFCCP and DFCCP can be summarized. In our preliminary investigations, the main results can be given as follows. ICP can make the density of SFCCP increase and the distribution of the electron temper- ature in a radial direction more uniform. In addition, ICP not only can make the ion density of DFCCP increase, but also can improve the radial uniformity. F^rther experiments may be needed to clarify the mechanism.
基金supported by the National Natural Science Foundation of China(Nos.11372325,11475239)
文摘The capacitively coupled plasma in the gaseous electronics conference reference reactor is numerically investigated for argon flow using a non-equilibrium plasma fluid model. The finite rate chemistry is adopted for the chemical non-equilibrium among species including neutral metastable, whereas a two-temperature model is employed to resolve the thermal non-equilibrium between electrons and heavy species. The predicted plasma den- sity agrees very well with experimental data for the validation case. A strong thermal non-equilibrium is observed between heavy particles and electrons due to its low collision frequency, where the heavy species remains near ambient temperature for low pressure and low voltage conditions （0. t Torr, 100 V）. The effects of the operating parameters on the ion flux are also investigated, including the electrode voltage, chamber pressure, and gas flow rate. It is found that the ion flux can be increased by either elevating the electrode voltage or lowering the gas pressure
