The shrinking dimensions of active devices on silicon chips are approaching its limit due to restrictions set by photolithographic techniques. For example, wave properties of radiation, such as interference and diffraction, can limit device size and density. Considerable research has taken place to overcome the limitations of photolithographic techniques.
In U.S Patent 7,633,080, Intel Corporation (Santa Clara, CA) inventor Valery M Dubin describes numerous embodiments of a method to assemble nano-materials on a platform, including the use of DNA to form electronic devices using carbon nanotubes. Two-dimensional or three-dimensional devices for use in semiconductor devices may be assembled from nano-materials such as carbon nanotubes, silicon nano-wires, metal nano-wires, or quantum dots. The nano-materials may be assembled on a platform to provide a bottom-to-top assembly method. The nano-materials may be functionalized with one or more deoxyribose nucleic acid (DNA) groups. The DNA functionalized nano-materials may form electrical interconnects or logic/memory integrated circuits.
In one embodiment, carbon nanotubes are functionalized with a first bondable group. The functionalized nano-material is disposed on an assembly platform having an electrode to form a first layer. Additional layers of carbon nanotubes may be formed above the first layer to form a semiconductor device.
Carbon-based nano-materials are considered one type of alternative materials for manufacturing active devices. One example of a nano-material is carbon nanotubes, which are tubular carbon molecules with properties that make them potentially useful in extremely small scale electronic and mechanical applications. They exhibit high strength and advantageous electrical properties, and are extremely efficient conductors of heat. Also, because of their unique dimensions and unusual current conduction mechanism, carbon nanotubes may be ideal components of electrical circuits, transistors, MEMS devices, interconnects, and other circuit elements.
One problem with using nano-materials such as carbon nanotubes in circuits relates to fabrication difficulties. The carbon nanotube production processes are very different from the traditional integrated circuit (IC) fabrication process in that a conventional top-to-bottom approach is not used (e.g., films are deposited onto a wafer and pattern-etched away). Today, there is no reliable way to arrange carbon nanotubes into a circuit. In one current fabrication method, carbon nanotubes are manipulated one-by-one with the tip of an atomic force microscope in a painstaking, time-consuming process. Intel's invention one of many steps the company has taken towards overcoming the problems of fabricating semiconductor devices with carbon nanotubes and other nanomaterials.
