| Radio frequency inductively coupled plasma (rf ICP) is widely used in plasma etching of microelectronic chip, deposition of semiconductor thin film, broad high-current ion source, plasma immersion ion implantation, chemical synthesis and crystal growth due to the advantage of the high plasma density at low gas pressure, simplified device and more precise control over spatial uniformity. In the research of rf ICP, how to improve the spatial uniformity of the plasma has been the important issues.In the present work, we explored the radial plasma characteristics profile of cylindrical inductively coupled plasma in weak magnetic field. Under the settled discharge conditions of discharge gas (Ar), pressure, absorbed power by plasma and coupled antenna, we measured the radial profile of plasma potential, electron temperature and electron density by the home-made Langmuir probe in weak magnetic field with different magnetic field strength and magnetic field configuration. The aim of the above work was to illustrate that how to configure an external magnetic field to cylindrical inductively coupled plasma could improve the uniformity.The experimental results were that the radial profile of plasma density changed gradually all around high and center low with the increase of axial magnetic strength. The cusped magnetic field gathered plasma to neutral region of magnetic field and the radial profile of plasma density in cusped magnetic field became central peaking. Therefore, when the radial profile of plasma density was center high and all around low, the axial magnetic field should be configured to cylindrical inductively coupled plasma to improve the uniformity. Otherwise, when the radial profile was all around high and center low, the cusped magnetic field should be configured. |
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