Influence of Thickness on Field Emission Characteristics of Nanometer Boron Nitride Thin Films

Nanometer boron nitride (BN) thin films with various thickness (54-135 nm) were prepared on Si(100) by rf magnetic sputtering physical vapor deposition. The field emission characteristics of the BN thin films were measured in an ultrahigh vacuum system. A threshold electric field of 11 V/μm and the highest emission current density of 24μA/cm² at a electric field of 23 V/μm were obtained for the about 54-nm-thick BN film. The threshold electric field increases with the increase of the thickness in the nanometer range. The Fowler-Nordheim plots show that electrons were emitted from BN to vacuum by tunneling through the potential barrier at the surface of BN thin films.