Damageless vacuum sealing of Si field emitters with CHF3 plasma treatment

Abstract

Surface modification of Si field emitters by CHF3 plasma is investigated for damageless vacuum sealing. The emission characteristics of nontreated Si field emitters and CHF3-plasma-treated Si field emitters were measured in an ultra-high-vacuum chamber and in a frit-sealed vacuum package. The vacuum sealing process decreased the emission currents from the nontreated Si field emitters by a factor of 10. On the contrary, the emission current from the CHF3-plasma-treated emitters did not change before and after the vacuum sealing process. Analysis by Auger electron spectroscopy and by x-ray photoelectron spectroscopy revealed that the CHF3-plasma-exposed Si surface was covered with SiC and fluorocarbon films. These carbon-related films work as a protective material in the sealing process. By using this method, we achieved the first operation of metal–oxide–semiconductor field-effect-transistor-structured Si field emitters in a vacuum package.