Intel Corporation (Santa Clara, CA) reveals composite metal films and carbon nanotube nanofabrication techniques for nano-electronic device applications in U.S. Patent 7,635,503.
Intel inventors Juan E. Dominguez, Valery M Dubin, Florian Gstrein and Michael Goldstein developed methods for the growing carbon nanotubes using composite metal films and subsequently forming nano-semiconductor devices.
A composite metal film is fabricated to provide uniform catalytic sites to facilitate the uniform growth of carbon nanotubes. They also developed methods to embed nanoparticles for carbon nanotube fabrication. The manufacturing method is capable of maintaining the integrity of the catalytic sites at temperatures used in carbon nanotube fabrication processes, 600 to 1100.degree. C.
Carbon nanotubes (CNTs) are promising materials for extending semiconductor device miniaturization due to their electron (ballistic transport) and heat transport properties. Carbon nanotubes having a higher thermal conductivity than diamond can be fabricated. In general, carbon nanotubes are fullerene-related structures consisting of cylindrical nanomeric structures of carbon atoms arranged in a hexagonal lattice. Carbon nanotubes can be single-walled or multi-walled (concentric). Carbon nanotubes can be formed, for example, at graphite electrodes during the arc-evaporation of carbon. Single-walled carbon nanotubes can be formed at graphite electrodes containing metals such as cobalt.
Carbon nanotubes having metallic or semiconducting properties can be fabricated. A number of applications for carbon nanotubes have been proposed and demonstrated. Carbon nanotubes can be used, for example, as nanowires in a nano-electronic device or as active components of nano-mechanical devices, such as field-effect transistors, electromechanical actuators, and field emitters in CNT field-emission displays.
Carbon nanotubes having metallic or semiconducting properties can be fabricated. A number of applications for carbon nanotubes have been proposed and demonstrated. Carbon nanotubes can be used, for example, as nanowires in a nano-electronic device or as active components of nano-mechanical devices, such as field-effect transistors, electromechanical actuators, and field emitters in CNT field-emission displays
FIG. 3 shows a scanning electron microscope image of carbon nanotubes grown at 800.degree. C. on a graded film fabricated using evaporated cobalt and iron metals.
Catalytic sites for CNT growth can be fabricated that are small, uniform, and regularly spaced. As compared to typical supported metal catalysts used for carbon nanotube growth, these catalytic sites are relatively resistant to catalyst metal surface diffusion and the resulting metal particle agglomeration and growth, at the operating temperatures used for carbon nanotube growth. Because uniform catalytic sites can be created and maintained throughout synthesis, increased control of the distribution and diameter of the carbon nanotubes created by chemical vapor deposition (CVD) can be achieved
