Development and studies on a compact electron cyclotron resonance plasma source

摘要

It is well known that electron cyclotron resonance (ECR) produced plasmas are efficient, high-density plasma sources and have many industrial applications. The concept of a portable compact ECR plasma source (CEPS) would thus become important from an application point of view. This paper gives details of such a CEPS that is both portable and easily mountable on a chamber of any size. It uses a fully integrated microwave line operating at 2.45 GHz, up to 800 W, cw. The required magnetic field is produced by a set of suitably designed NdFeB ring magnets; the device has an overall length of approximate to 60 cm and weighs approximate to 14 kg including the permanent magnets. The CEPS was attached to a small experimental chamber to judge its efficacy for plasma production. In the pressure range of 0.5-10 mTorr and microwave power of approximate to 400-500 W the experiments indicate that the CEPS is capable of producing high-density plasma (approximate to 9 x 10(11)-10(12) cm(-3)) with bulk electron temperature in the range approximate to 2-3 eV. In addition, a warm electron population with density and temperature in the range approximate to 7 x 10(8)-10(9) cm(-3) and approximate to 45-80 eV, respectively has been detected. This warm population plays an important role at high pressures in maintaining the high-density plasma, when plasma flow from the CEPS into the test chamber is strongly affected.