DIAMOND-COATED TIPS AND THEIR APPLICATIONS

Scanning tunneling microscope (STM) has recently demonstrated its pote ntial application as a powerful tool for nanometer-scale surface modif ication. We have successfully fabricated new types of diamond-coated S TM tips by using microwave plasma chemical vapor deposition (MPCVD). T he reactant is a gaseous mixture of methane and hydrogen, sometimes ad ding oxygen. While natural diamond is a good insulator, the electrical conductivity of diamond-coated tips made by MPCVD technique is always high enough for STM experiments. These tips are quite stable, hard en ough to make machining on metal or other solid surfaces in nanometer s cale. We have applied the diamond coated STM tip to so-called controll ed machining on the metallic surfaces, such as gold, silver, and plati num films, and even polycrystal platinum, single crystal nickel, and p alladium. Further investigations, including the results caused by diff erent tips, applications for nanometer-scale processing and engineerin g, etc., have been discussed. This technique might become a potential useful tool for nanometer science and technology in the future.