Effect of tungsten implantation on electron field emission properties of ion-beam-synthesized SiC layers

摘要

The effect of tungsten implantation on the electron field emission (FE) properties of ion-beam-synthesized (IBS) SiC/Si heterostructures was studied and correlated to their microstructures and surface morphology. The turn-on field of the IBS SiC layers is improved from 25 to 14 V/μm after W implantation and is further decreased to 10 V/μm after thermal annealing at 1200℃ for 1 h. The improvements in FE properties after W implantation can be attributed to the formation of WC as well as two types of local field enhancement mechanisms. In the as-implanted sample, the local field enhancement effect is attributed to electrical inhomogeneity due to the formation of conducting WC nanoclusters embedded in the SiC layers. In the annealed samples, the dominated field enhancement is attributed to a surface morphology effect due to the formation of small protrusion structures at the surface.