Field emission from ultrathin coatings of AlN on Mo emitters

Experiments characterizing both the physics of emission and the performance of Mo tips coated with ultrathin Nm of AW were conducted. Ultrathin films of AIN with thicknesses ranging from 7 to 21 nm in 1.5 nm increments were deposited onto Mo tips by magnetron sputtering. In situ field emission measurements were performed after each deposition step. Tip radius, thickness, and morphology of AlN coating were characterized with the transmission electron microscopy. The effect of the thickness of AIN on emission was determined using a Fowler-Nordheim analysis. Various surface treatment effects were studied and measurements of maximum current and emission stability were performed, e.g., maximum current from a single Mo tip with 15 nm of AlN coating was 52 muA. (C) 2001 American Vacuum Society.