Design, fabrication, and characterization of self-aligned gated silicon field emission devices

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منو

" Design, fabrication, and characterization of self-aligned gated silicon field emission devices "
M. R. Rakhshandehroo S. W. Pang

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	1113350
Doc. No	:	TLpq304432115
Main Entry	:	M. R. Rakhshandehroo
	:	S. W. Pang
Title & Author	:	Design, fabrication, and characterization of self-aligned gated silicon field emission devices\ M. R. RakhshandehrooS. W. Pang
College	:	University of Michigan
Date	:	1998
student score	:	1998
Degree	:	Ph.D.
Page No	:	196
Abstract	:	A self-aligned process was developed for the fabrication of gated Si field emission devices with precise control on the gate-tip spacing, gate diameter, tip sharpness, and tip position. Emitter tips were etched in Cl2 plasmas generated by electron cyclotron resonance and inductively coupled plasma sources and a mask erosion technique was employed to control the emitter profile. Plasma oxidation was used to sharpen emitters to produce a tip radius of 8 nm and a gate-tip spacing of 80 nm. Arrays of uniform gated Si field emitters with high packing density of usd1.1\times10\sp7usd tips/cm2 were fabricated. Effects of device geometry on the emission characteristics were studied. At a gate voltage of 100 V, the emission current from an array of 100 emitters with 250 nm gate-tip spacing increased from 261 to 598 muA and the turn-on voltage decreased from 39 to 20 V when the emitter tip radius was reduced from 67 to 8 nm by sharpening with plasma oxidation. The turn-on voltage of the emitters decreased from 67 to 16 V when the gate-tip spacing was decreased from 500 to 193 nm by growing a thinner plasma oxide. Surface passivation using Cl2 or H2 plasma improved the emission characteristics of Si field emission devices. The emission current increased from 152 to 185 muA after Cl2 plasma passivation and from 284 to 460 muA after H2 plasma passivation. These increases in the emission current correspond to a 0.5 eV and 1.28 eV reduction in the effective work function of the emitters, respectively. Emitter tips were also coated with Mo silicide and HfC to enhance their emission characteristics. The turn-on voltage decreased from 50 V for uncoated emitters to 41 V with Mo coating and 25 V with HfC coating. The decreased turn-on voltage is attributed to 0.95 and 2.23 eV reduction in the work function of the emitters after Mo silicide and HfC coating, respectively. These gated Si field emission devices show substantial improvements in emission characteristics, uniformity, and stability compared to previously reported results. Their excellent device characteristics are most suitable for flat panel displays and high power microwave amplifiers.
Subject	:	Applied sciences
	:	Electrical engineering
	:	Field emission devices
	:	Self-aligned
	:	Silicon