Improvement and characteristics of conical silicon emitters employing wet-dry etching
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A number of new technologies require conical and sharp tips to serve as electron emitters in the vacuum microelectronics. In this paper, we improved radius of curvature, height and cone angle of emitters in order to reach the enhancement result of field enhancement factor (β). We developed a fabrication process to improve geometry of emitter by employing isotropic dry etching in pure SF6 and a mixture of SF6 and O2 followed by thermal oxidation technique. We successfully achieved excellent conical emitters with 5–10 nm radius of curvature, 4.4 μm height, and 30° cone angle. The conical silicon emitters current–voltage characteristics shows that Eto = 4.8 V/μm (turn-on electric field) with current density of 10 μA/cm2, and maximum current density J = 60.4 μA/cm2 at E = 8.14 V/μm. This study may provide a practical guideline for design and fabrication of a high-performance silicon emitter used in various industrial applications.
KeywordsCone Angle SiH4 Maximum Current Density Emission Current Density Field Emission Characteristic
This work was supported by the National Science Council of Taiwan under Grant numbers of NSC-99-2221-E-158-009, and Shih Chien University Kaohsiung Campus under contract numbers of USC-101-05-05005 and USC-101-08-01004. Also partially supported by National Science Council, R.O.C. under contract NSC 100-2221-E-020-018 and the SEM work was partially performed in the Precision Instruments Center of NPUST. Thank the Nano Device Laboratories to provide comprehensive laboratory equipment, and technical support.