Granite Countertops

Intel Carbon Nanotube Capacitors to Deliver Power to Electronic Devices, Overcome Limitations of Ceramic Capacitors

Intel Corporation (Santa Clara, CA) garnered U.S. Patent 7,710,709 for its carbon nanotube coated capacitor electrodes and their manufacturing method as well as the resulting capacitors. The capacitors are intended to deliver power to electronic devices.  The capacitor may be used in desktop computers, workstations, servers, mainframes, laptops, handheld computers, handheld gaming devices, handheld entertainment devices (for example, a video player), PDAs (personal digital assistant), and telephony devices (wireless or wired) to name a few examples.
 
In one embodiment, a device includes a substrate and a capacitor is formed on the substrate. The capacitor includes first and second electrodes and a capacitor dielectric between the first and second electrodes. At least one of the first and second electrodes includes a metal layer having carbon nanotubes coupled thereto, according to inventors Yongki Min and Daewoong Suh (Phoenix, AZ).
In one aspect of certain embodiments, the carbon nanotubes are at least partially coated with an electrically conductive material. In another aspect of certain embodiments, the substrate comprises an organic substrate and the capacitor dielectric comprises a polymer material.

FIG. 1 illustrates a photomicrograph of a multi wall carbon nanotube (MWCNT) array grown on a substrate for use in capaictors. The carbon nanotubes have a structure that includes a relatively large surface area. 

The carbon nanotubes provide a substantially larger exposed surface area than a conventional capacitor electrode surface. For instance, an electrode having carbon nanotubes may in certain cases have a surface area some 400-30,000 times greater than a flat surface electrode capacitor. Carbon nanotubes may be grown using a suitable method such as plasma-enhanced chemical vapor deposition (PECVD).
Catalysts are generally used to assist in the nanotube growth, and it is believed that metals including, but not limited to, nickel, iron, cobalt, molybdenum, and ruthenium, and their compounds, are effective catalysts. As a result, such metals may be applied to a substrate surface, for example, copper, using a suitable formation process such as, for example, a physical vapor deposition (PVD) process, and then the carbon nanotubes formed thereon. Alternatively, the carbon nanotubes may be formed directly onto metallic substrates or foils formed from such materials. The layer may be formed on the nanotubes using any suitable formation process, for example, a vapor deposition or a plating process. In certain embodiments, the layer  may be formed from a metal such as copper or gold. 
Due to the large surface area of the carbon nanotubes, a large capacitance may be obtained when using a relatively low dielectric constant material as the capacitor dielectric. For instance, ceramic dielectric materials with high dielectric constants are often used for high capacitance capacitors. In certain embodiments, the use of the carbon nanotubes permits high capacitance to be obtain when using polymer dielectric materials having a lower dielectric constant than ceramic dielectric materials. For example, due to the larger surface area of the electrode with carbon nanotubes coupled thereto, in certain embodiments, a polymer dielectric having a dielectric constant of 5 may be used, whereas in a conventional ceramic thin film dielectric capacitor, a ceramic material having a dielectric constant of 1000 may be used. As a result, it is believed that in certain applications, embodiments of embedded capacitors having a polymer dielectric and one or more carbon nanotube coated electrodes can be used as an alternative to multi-layer ceramic chip (MLCC) capacitors.