Mark Ray

High field emission reproducibility and stability of carbon nanosheets and nanosheet-based backgated triode emission devices

The authors have characterized field emission properties of freestanding, 1nm thick graphene layers, called carbon nanosheets (CNSs), which were grown perpendicular to the growth surface using a radio-frequency plasma-enhanced chemical vapor deposition technique. The CNSs are metallic impurity-free and have uniform height distribution (standard deviation of 200h at 1.3mA emission current level. Over this time, no degradation has been observed, the variability of the individual I-V curves is small among 7216 voltage cycles, and the standard deviation at the maximum current was no more than 2.3%. A nanosheet-based backgated triode emission device has been developed to take advantage of the nanosheet field emission performance. Prototype devices have confirmed triode operation and stable electron emission.

Selective plasma deposition

A deposition process provides selective areal deposition on a substrate surface having separate areas of different materials comprises forming a plasma over the substrate, injecting coating species into the plasma by either of sputtering or gaseous injection, adding a reactive gas for altering surface binding energy at the coating surface, and biasing the substrate during deposition to bombard the substrate with ionic species from the plasma. Surface binding energy is altered, in the general case, differently for the separate areas, enhancing selectivity. Bias power is managed to exploit the alteration in surface binding energy. In the case of gaseous injection of the coating species, and in some cases of sputtering provision of the coating material, the temperature of the substrate surface is managed as well. In an alternative embodiment, selectivity is to phase of the coating material rather than to specific areas on the substrate, and a selected phase may be preferentially deposited on the substrate.

Back-gated milliampere-class field emission device based on carbon nanosheets

The fabrication and testing of a back-gated field emission device (bgFED) are reported. The properties of a unique allotrope of carbon, carbon nanosheet (CNS), are exploited for use as a highly effective field emitter material, and CNSs are incorporated into a bgFED capable of producing several milliamperes of emission current. The bgFED is evaluated in terms of triode modulation, high current capability, and short-term stability.

Buried-Line Back-Gated Triode Field Emission Devices

Reported in this paper is recent work on a new type of back-gated triode device. Fabrication of the device and modeled performance predictions are discussed

Milliamp-Class, Back-Gated, Triode Field Emission Devices Based on Free-Standing, Two-Dimensional Carbon Nanostructures

In this presentation we discuss recent results using carbon nanosheets (CNS) as the field emission source in a back gated device for high current applications

Carbon nanotubes field emitter and back-gated structure

Carbon nanotubes (CNTs) were synthesized by radio frequency (RF) plasma enhanced chemical vapor deposition (PECVD) method on nanoscaled nickel particles as catalyst formed by both a nanosphere lithography (NSL) method and by a plasma pre-treatment of Ni layers on silicon substrates. These CNTs was studied as field emission materials using a novel triode structure for field emission device design by a back-gated structure. Field emission of this back-gated device was characterized using a triode I-V curve measurement.

Synthesis and field emission properties of carbon nanosheets

A nanometer edged two-dimensional graphite structure, carbon nanosheet, was synthesized by inductively coupled radio-frequency plasma enhanced chemical vapour deposition on a variety of substrates, including metals, semiconductors and insulators. The carbon nanosheets were characterized by scanning electron microscopy, high resolution transmission electron microscopy and Raman spectroscopy. Edges of nanosheets had a uniform thickness of about 1 nm. Typical nanosheets consisted of only a few atomic layers and had a graphitic structure. The high density of atomic scale vertical graphitic edges are potential sites for electron field emission. The carbon nanosheets had a turn-on (threshold 10/spl mu/A/cm/sup 2/) field of about 5 V//spl mu/m and a metallic behavior based on a linear Fowler-Nordheim plot. This sheet-like carbon nanostructure is expected to be a robust edge emitter.

Development of a low permittivity fluorinated copolymer for interlevel dielectric applications

Technology for future integrated circuits will require advances in all facets of materials and processing. Low dielectric constant materials will require advances in electrical, thermal, and mechanical behavior before process integration can occur. The dielectric constant must be lower than that of amorphous silicon dioxide and possess the right properties for integration with future metallurgies such as copper. Several organic thermoset resins that were predicted to possess the necessary characteristics have been synthesized and studied. A thermoset copolymer of 1,3,5-tris(2-allyloxy-hexafluoro-2-propyl) benzene with polymethylhydrosiloxane oligomers was identified as a material worthy of further development. Thermal gravimetric analysis indicates relative stability up to 350 °C for short periods of time (30–60 min). The complex permittivity was measured up to 40 GHz and was found to be 2.40 with a loss tangent of 0.008. Compatibility with copper multilevel processing was determined by a secondary ion ma...