DIRECT SUPPORT BY SPOT WELDING AND CHEMICAL ETCHING OF COMPOUND SEMICONDUCTOR WHISKER

Abstract
When electron and ion beams of angstrom order using fine emitter tips with small radius can be obtained easily, we have some merits in the field of the electron microscope with high resolution, the micro-fabrication technology and the scanning tunneling microscope. For this purpose, we have been experimented the properties of a compound semiconductor whiskers (SiC, GaAs and GaP) with various angle as emitter materials. This time, we tried to use SiC whiskers which have very small diameter (0.2 ~ 1 µm Ø). They can't be seen directly with eye but can be seen only with the reflection of the light. These whiskers are β-SiC type with Zinc-blende structure. Mounting of SiC whisker to hairpin loop is not easy because of their small diameter and the high melting point. In this article, the direct mounting method with spot welding and electro chemical etching to obtain fine tip are presented. Electro chemical etching of the whisker was performed by using etching solution film streched inside of platinum ring. Those emitters obtained by this method had a radius of below 300 angstrom and their surfaces were extremly smooth. For the other compound semiconductor (GaAs and GaP), we are also obtained useful emitter by the above treatment.