FABRICATION OF DIAMOND TIPS BY THE MICROWAVE PLASMA CHEMICAL-VAPOR-DEPOSITION TECHNIQUE

Scanning tunneling electron microscopy (STM) has recently shown great promise for surface modification in the nanometer regime. As is well k nown, the normal STM tips are easily damaged by mechanical contact wit h the sample surface in most cases. In this paper we describe a new ty pe of diamond STM tip prepared by the microwave plasma chemical vapor deposition technique. The reactant is a gas mixture of methane and hyd rogen. Diamond crystals are grown on a tungsten tip. The diamond tips are very hard and always have enough electrical conductivity for STM e xperiments. They can be used as a machining tool to scratch the metal surfaces.