High Quality Shadowing Using Point Evaporator

• Published in: Journal of electron microscopy 1975-01, Vol.24 (4), p.227-233
• Main Authors: MATSUI, Shigeo, KAWAKATSU, Hisazo, ADACHI, Koichi
• Format: Article
• Language: English
• ISSN: 0022-0744; 1477-9986; 1477-9986
• DOI: 10.1093/oxfordjournals.jmicro.a049975

A point evaporator using electron beam bombardment Is developed, and the application to high quality shadowing is tried. The evaporator consists of an anode of evaporant wire, a ring shaped cathode and two electrodes for focusing of elctron beam and for shielding of radiation from cathode. Electron beam emitted from the cathode ts focused on the tip of the anode wire, and then the anode material is evaporated from the tip. By using the evaporator, the refractory materials such as W, Ta, Mo and Pt-Pd can be easily evaporated with high stability and good reproducibillty. With aim of attaining the high quality shadowing with the evaporator, basic study on sharpness of shadowing is performed and the dependence of sharpness on the evaporation source size, the shadowing angle and the vacuum condition is quantitatively obtained. Evaporated W films of roughly 10 Å in thickness show undetectable grain structure and satisfactory contrast In 100 keV electron microscopic observations, and the W-shadow for a sample of sputtered Al particles of greater than 30 Å in diameter on carbon substrate can be clearly observed.