Recent development of diamond microtip field emitter cathodes and devices

Abstract

Subvolt turn-on voltage self-align gate diamond emitter fabricated by self-align-gate-sharpened molding technique J.Recent development of diamond field emitter cathodes and devices fabricated from molding process is presented. Practical modifications involving the sp 2 content, surface treatment, boron doping, and tip sharpening to further enhance diamond field emission are discussed. A new fabrication process for achieving ultrasharp diamond tips with a radius of curvature less than 5 nm has been achieved and shows significant improvement in emission characteristics. Discussion of this enhanced emission in diamond microtips is presented in accordance with analysis of emission behavior. The development of high site density of uniform diamond microtip arrays is presented. We also report the development of a new technique to fabricate self-aligned gate diamond emitter diodes, which achieve very high emission characteristics at extremely low applied voltage. The latest development aims to integrate diamond field emitters with silicon-based MEMS processing technology and achieve totally monolithic diamond field emitter devices on silicon wafers. Preliminary results in the triode configuration demonstrate promising transistor characteristics suitable for vacuum microelectronic applications.

Origin of graphitic filaments on improving the electron field emission properties of negative bias-enhanced grown ultrananocrystalline diamond films in CH4/Ar plasma

“…As shown in Fig. 7(c), there exists a donut-shaped diffuse ring in ft 6 image, inferring the presence of graphitic phase in region 6, and there presents parallel fringes in region 5 with rel-rods in ft 5 image, indicating the presence of stacking faults in the large diamond aggregates. Both the donut shaped diffraction ring in ft 6 image and rel-rods in ft 5 image are of larger contrast, revealing that the graphitic phase in region 6 is better crystallized and the stacking faults in region 5 is more defective due to the application of À200 V bias voltage.…”

“…[1][2][3][4] The negative electron affinity (NEA) characteristic of diamond films observed for re-structured (100) surface was thought to be of immense prospective for applications as electron field emitters. 5,6 However, a good diamond electron field emitter requires, besides the NEA surface, sufficient supply of electrons from the back electrode materials and efficient transport of electrons through the diamond. The diamond films, which were grown in CH 4 /H 2 plasma, usually contain large grains [microcrystalline diamond (MCD)] with a large electron bandgap (5.1 eV).…”

Processing of Diamond for Integrated Optic Devices Using Q-Switched Nd:YAG Laser at Different Wavelengths

“…The use of diamond enables higher operating speed, as devices can be more tightly packed without overheating. Further reliability improvements should be expected, as the junctions in the devices will be operating at lower temperature when mounted on diamond [1][2][3]. The electronic structure of diamond has a wide bandgap, giving it the potential for use as a semiconductor.…”

“…The above properties are all related to the strength of the carbon bonds in the crystal and its structure. Major advantages for the use of diamond technology for applications such as integrated optical and UV optoelectronic devices, sensors, micro electromechanical systems, and high power devices are its superior electronic properties at much higher temperatures and harsh environments such as high breakdown voltage, electron saturation velocity, carrier mobility, thermal conductivity, and electrical stability [1][2][3][4]. Electrical devices based on wide bandgap (WBG) semiconductors such as diamond allow operation at high frequencies and temperatures.…”

“…The devices are capable of operating at temperatures > 600 • C compared with a maximum operating temperature of 200 • C for silicon and gallium arsenide devices. Potential applications include very high power transistors, high temperature integrated circuits, piezoelectric devices, and radiation hardened integrated circuits [2][3][4].…”