Ion parameters in electron cyclotron resonance （ECR） microwave plasma were measured by ion sensitive probe and were compared with the electron parameters obtained by double Langmuir probe. The effects of gas pressur...Ion parameters in electron cyclotron resonance （ECR） microwave plasma were measured by ion sensitive probe and were compared with the electron parameters obtained by double Langmuir probe. The effects of gas pressure and microwave power on the ion temperature and density were analyzed. The spatial distribution of the ion parameters was also investigated by the ion sensitive probes with a tunable radial depth installed on different probe windows along the chamber axis. Results showed that the ion density measured by the ion sensitive probe was in good agreement with the electron density measured by the double Langmuir probe. The influ- ence of gas pressure on the ion parameters was stronger than that of microwave power. With the increase in working pressure, the ion temperature decreased monotonously with a decreasing rate larger than that at higher pressure. The ion density first increased to a peak （42.3~ 101~ cm-3） at 1 Pa and then decreased. The ion temperature and density increased little with the increase in the microwave power from 400 W to 800 W, The plasma far away from the resonant point is found to be radially uniform.展开更多
An algorithm for automated fitting of the effective electron temperature from a planar Langmuir probe I-V trace taken in a plasma with multiple Maxwellian electron populations is developed through MATLAB coding.The co...An algorithm for automated fitting of the effective electron temperature from a planar Langmuir probe I-V trace taken in a plasma with multiple Maxwellian electron populations is developed through MATLAB coding.The code automatically finds a fitting range suitable for analyzing the temperatures of each of the electron populations.The algorithm is used to analyzeⅠ-Ⅴtraces from both the Institute of Plasma Physics Chinese Academy of Sciences's Diagnostic Test Source device and a similar multi-dipole chamber at the University of Wisconsin-Madison.Ⅰ-Ⅴtraces reconstructed from the parameters fitted by the algorithm not only agree with the measured I-V trace but also reveal physical properties consistent with those found in previous studies.Cylindrical probe traces are also analyzed with the algorithm and it is shown that the major source of error in such attempts is the disruption of the inflection point due to both decreased signal-to-noise ratio and greater sheath expansion.It is thus recommended to use planar probes with radii much greater than the plasma Debye length when signal-to-noise ratio is poor.展开更多
A Langmuir probe plasma diagnostic system was developed to measure the plasma parameters in a PECVD vacuum coating machine. The plasma was a capacitively coupled plasma （CCP） driven by a radio-frequency （RF） power...A Langmuir probe plasma diagnostic system was developed to measure the plasma parameters in a PECVD vacuum coating machine. The plasma was a capacitively coupled plasma （CCP） driven by a radio-frequency （RF） power supply. To avoid the disturbance of radio-frequency field on the Langmuir probe measurement, a passive compensation method was applied. This method allowed the ＇dc＇ component to be passed and measured in the probe circuit. It was found that the electron temperature in the range from 2.7 eV to 6.4 eV decreased with the increase in RF power. The measured plasma density ranged from 8×10^16 m^-3 to 0.85×10^15 m^-3 and increased with the increase in RF power.展开更多
基金supported by National Natural Science Foundation of China (No. 10875093)
文摘Ion parameters in electron cyclotron resonance （ECR） microwave plasma were measured by ion sensitive probe and were compared with the electron parameters obtained by double Langmuir probe. The effects of gas pressure and microwave power on the ion temperature and density were analyzed. The spatial distribution of the ion parameters was also investigated by the ion sensitive probes with a tunable radial depth installed on different probe windows along the chamber axis. Results showed that the ion density measured by the ion sensitive probe was in good agreement with the electron density measured by the double Langmuir probe. The influ- ence of gas pressure on the ion parameters was stronger than that of microwave power. With the increase in working pressure, the ion temperature decreased monotonously with a decreasing rate larger than that at higher pressure. The ion density first increased to a peak （42.3~ 101~ cm-3） at 1 Pa and then decreased. The ion temperature and density increased little with the increase in the microwave power from 400 W to 800 W, The plasma far away from the resonant point is found to be radially uniform.
基金This work is supported by the Chinese Academy of Science Hundred Youth Talent Program Start-up Funding,CAS Key Research Program of Frontier Sciences(No.QYZDB-SSW-SLH001)National Natural Science Foundation of China(Nos.11875285,11575248 and 11505220)well as US National Science Foundation Award(No.1804654).
文摘An algorithm for automated fitting of the effective electron temperature from a planar Langmuir probe I-V trace taken in a plasma with multiple Maxwellian electron populations is developed through MATLAB coding.The code automatically finds a fitting range suitable for analyzing the temperatures of each of the electron populations.The algorithm is used to analyzeⅠ-Ⅴtraces from both the Institute of Plasma Physics Chinese Academy of Sciences's Diagnostic Test Source device and a similar multi-dipole chamber at the University of Wisconsin-Madison.Ⅰ-Ⅴtraces reconstructed from the parameters fitted by the algorithm not only agree with the measured I-V trace but also reveal physical properties consistent with those found in previous studies.Cylindrical probe traces are also analyzed with the algorithm and it is shown that the major source of error in such attempts is the disruption of the inflection point due to both decreased signal-to-noise ratio and greater sheath expansion.It is thus recommended to use planar probes with radii much greater than the plasma Debye length when signal-to-noise ratio is poor.
基金the Enterprise Postdoctoral Research Fund of Liaoning Province(BSH:2004921032)National Natural Science Foundation of China(No.60774093)
文摘A Langmuir probe plasma diagnostic system was developed to measure the plasma parameters in a PECVD vacuum coating machine. The plasma was a capacitively coupled plasma （CCP） driven by a radio-frequency （RF） power supply. To avoid the disturbance of radio-frequency field on the Langmuir probe measurement, a passive compensation method was applied. This method allowed the ＇dc＇ component to be passed and measured in the probe circuit. It was found that the electron temperature in the range from 2.7 eV to 6.4 eV decreased with the increase in RF power. The measured plasma density ranged from 8×10^16 m^-3 to 0.85×10^15 m^-3 and increased with the increase in RF power.
