Secondary electron imaging at gas pressures in excess of 1 kPa

Abstract

Environmental scanning electron microscopy (ESEM) enables electron imaging of gas-mediated, direct-write nanolithography processes, liquids, and hydrated biomaterials. However, ESEM is limited by poor image quality at gas pressures in excess of ∼600 Pa. Here the authors achieve high quality secondary electron imaging at 2 kPa of H2 O by optimizing boundary conditions that govern beam scatter and the energy distribution of low energy electrons in the gas, dielectric breakdown of the gas, and detector collection efficiency. The presented high pressure imaging method will enable imaging of hydrated materials at close to room temperature, and gas-mediated surface modification processes occurring at high pressures. © 2007 American Institute of Physics.