Field Electron Emission under Extreme High Vacuum and Extreme High Vacuum Technology of Korea

Abstract

  An extreme high vacuum field emission microscope (XHV-FEM) was constructed for the study of inherent fluctuations of field emission (FE) current. The damping and fluctuation behaviors of FE from clean W(111) tips at 90 K were observed using the XHV-FEM. The noise of FE currents ranging from 10 pA to 100 μA was measured under ~7×10^-10 Pa. Stepwise features were routinely observed in damping curves of the FE current, indicating remarkable sensitivity of the FE current measuring system. The lowest frequency measurement of shot noise was recorded even at 4 Hz. Semilogarithmic damping curves of FE currents were linear in our thoroughly degassed XHV-FE system. The slope of semilogarithmic damping curves was linearly proportional to the operation pressure, suggesting a method of measuring pressure in an XHV range. An introduction to the XHV technology of Korea is also presented.