Hard mask fabrication for magnetic random access memory elements using focused ion beam assisted selective chemical vapor deposition

A study to investigate the fabrication of carbon masks for very small magnetic tunnel junctions (MTJ) using focused ion beam assisted selective chemical vapor deposition was presented. The gaseous phenanthrene that was absorbed on the sample surface, decomposed into solid carbon by irradiation with a Ga ion beam. The carbon layer deposited demonstrated a lower(higher) etching rate for Ar(O₂) ion etching. The results showed that the width of the carbon mask patterns varied from about 30 to 500 nm.