UHV STM NANOFABRICATION - PROGRESS, TECHNOLOGY SPIN-OFFS, AND CHALLENGES

A brief review of scanned probe nanofabrication is presented followed by an in-depth discussion of ultrahigh vacuum (UHV) scanning tunneling microscope (STM) nanofabrication on hydrogen passivated silicon surfa ces. In this latter case the UHV STM functions as a nanolithography to ol by selectively desorbing hydrogen from silicon surfaces. Patterns o f clean Si, down to atomic dimensions, are achieved as well as detaile d information about the H-desorption mechanisms. At higher sample volt ages direct electron stimulated desorption occurs, whereas, at lower v oltages, vibrational hearing of the Si-H bond leads to desorption. The chemical contrast between clean and H-passivated silicon enables a wi de variety of spatially selective nanoscale chemical reactions. Result s are presented in which these templates are used far selective oxidat ion, nitridation, and metallization by chemical vapor deposition. An u nexpected byproduct of this research was the discovery that deuterium is about two orders of magnitude more difficult to desorb from silicon than hydrogen. This sewed as the basis for the idea of treating CMOS transistors with deuterium to reduce their susceptibility to hot carri er degradation effects. Tests have now shown that the lifetimes of CMO S transistors increase by factors of 10 to 50 when deuterium treatment is substituted for the traditional hydrogen processing.