SOLID-STATE CESIUM ION GUN FOR ION-BEAM SPUTTER DEPOSITION

A compact cesium ion gun, suitable for ion beam sputter deposition in high vacuum environment, has been developed. The gun uses a solid-state cesium ion source described previously. This gun is compact, stable, and easy to use. It requires none of the differential pumping or associated hardware necessary in designs using cesium vapor and porous tungsten ionizers. The gun produces a cesium ion beam of 0.2 mA at 5 keV. A beam diameter of 0.2 cm is measured at a target which is 3 cm apart from the exit aperture of the accelerator electrode. The sputter deposition rate is of the order of 100 angstrom/min for several metal targets such as Au, Cu, Mo, W, and Ta, measured at 4 keV primary Cs+ ion beam energy and in a distance of 1.5 cm from the target. The lifetime of this gun is more than 20 C of cesium, which corresponds to 60 h of operation with an extraction current of 0.1 mA.