The tectra IonEtch ion gun is a filamentless ion source based on a microwave plasma discharge. Like its big brother the Plasma Ion Source, the IonEtch sputter gun works by coupling microwave energy into a coaxial waveguide and from there via evanescent wave coupling, into a plasma chamber. The intense oscillating electric fields cause the gas to breakdown and a plasma discharge to take place. An quadrupole magnetic field around the plasma chamber further enhances the plasma density via the Electron Cyclotron Resonance (ECR) effect. Ions are extracted from the plasma using simple two or three grid single-hole extraction optics.
The use of microwaves to sustain the plasma allows ions to be extracted at very low energies without the plasma collapsing (down to 25eV) and since there are no hot metal electrodes in the plasma also permits the use of reactive gases such as oxygen and hydrogen.