Theoretical determination of electron temperature in electron-cyclotron plasmas
- Naval Surface Warfare Center, Silver Spring, MD (United States)
- Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of)
A basic theory of the plasma electron temperature in ECR plasmas has been reported in recent studies in connection with application to the plasma etching technologies. However, the previous theoretical study of the ECR plasmas is primitive and ad hoc. The authors therefore develop a theory for plasmas generated by the electron-cyclotron-resonance (ECR) mechanism and an experiment is conducted to compare the theoretical prediction and experimental measurements. Due to a large electron mobility along the magnetic field, electrons move quickly out of the system, leaving ions behind and building a space charge potential, which leads to the ambipolar diffusion of ions. In a steady-state condition, the plasma generation by ionization of neutral molecules is in balance with plasma loss due to the diffusion, leading to the electron temperature equation, which is expressed in terms of the plasma size, chamber pressure, and the ionization energy and cross section of neutrals. The electron temperature decreases as the chamber pressure increases. Based on the ambipolar diffusion of ions, a self-consistent theory of the plasma density profile is developed. The power balance condition leads to the plasma density equation, which is also expressed in terms of the electron temperature, the input microwave power and the chamber pressure. It is shown that the plasma density increases, reaches its peak and decreases, as the chamber pressure increases from a small value (0.1 mTorr). After carrying out an experimental observation, it is concluded that the theoretical predictions of the electron temperature and plasma density agree remarkably well with experimental data.
- OSTI ID:
- 160765
- Report Number(s):
- CONF-950612-; ISBN 0-7803-2669-5; TRN: IM9603%%347
- Resource Relation:
- Conference: 22. international conference on plasma science, Madison, WI (United States), 5-8 Jun 1995; Other Information: PBD: 1995; Related Information: Is Part Of IEEE conference record -- abstracts: 1995 IEEE international conference on plasma science; PB: 312 p.
- Country of Publication:
- United States
- Language:
- English
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