Emission characteristics of ion-implanted silicon emitter tips

An ion implantation technique has been applied to control the energy band structure of Si field-emitter tip surface. B+ or P+ ions were implanted after fabrication of a gated emitter structure. No changes in emitter structure were observed after ion implantation and successive annealing at 800 degrees C., Current-voltage (I-V) characteristics of n,p,p/n and n/p emitter tips were measured: p/n indicates an n-type tip with B+ ions implanted into the tip surface. It was found from the experimental results that n and n/p tips had I-V characteristics in agreement with the Fowler-Nordheim theory. The p and n/p tips, on the other hand, exhibited a current saturation property in high electric field. The present saturation mechanism is explained by considering the energy band structure of the tip surface.