DISCHARGE CHARACTERISTICS OF A 5 CM MULTIPOLAR ELECTRON-CYCLOTRON-RESONANCE ION-SOURCE

A compact 5-cm-diam multipolar electron cyclotron resonance (ECR) ion source is characterized. The source is experimentally studied with no grids using argon gas with 50-250 W of 2.45-GHz microwave input power. Using a microcoaxial probe it was confirmed that the exciting electro magnetic fields within the resonant cavity were indeed TE111, as expec ted from the critical cavity dimensions. Double Langmuir probe measure ments indicate high densities of about (4-5) x 10(11)/cm3 near the sou rce, and 5 cm downstream from the source output the densities become v ery uniform with a value of about 5 x 10(10)/cm3 over a 10-cm diameter . Electron energy distribution functions (EEDF) were measured using a single Langmuir probe. Average electron energies were seen to be about 8-10 eV with an energy distribution function falling between a Maxwel lian and a Druyvesteyn distribution. Ion energy distribution functions (IEDF) were measured with a multigrid energy anlalyzer. It was seen t hat the distribution functions were narrow and peaked [with a full wid th half maximum (FWHM) of about 5 eV] except under certain conditions. Above 200-W input power, and also below about 0.5 mTorr there is sign ificant broadening of the ion distribution function. It is speculated that the former may be caused by gas heating, and the latter may be ca used by the presence of Ar+2 ions. With its high current densities (>1 0 mA/cm2) and low average ion energies (<40 eV), it is expected that t his ion/plasma source will be very useful in many etching and depositi on applications.