Surface Treatment Effects on the Electron Emission Characteristics of Ultra Thin AIN Coated Molybdenum Tips

Although plasma surface treatment has proven useful for both metal and diamond field emitters, there is at this time no study of the effect of plasma treatment on the field emission from a thin layer of AIN. In this study a 7 nm film of AIN deposited on a molybdenum emitter tip was treated with different plasmas (H2, O2, and N2). All surface treatments and measurements were carried out by using an in-situ technique inside the magnetron sputtering chamber. Changes in the measured I-V curves were not observed from the emitter after treatment with either hydrogen or nitrogen plasmas, but were observed after oxygen plasma treatment. In addition, it was found that a very thin coating of aluminum over the AIN further enhanced the emission characteristics. We propose that the lowering of the surface barrier is due to the electronegativity difference of the species forming the surface layer.