Preparation of diamond whiskers using Ar/O_2 plasma etching

摘要

Radio frequency (RF) plasma etching of chemical vapor deposition (CVD) diamond film has been investigated in Ar/O_2 plasmas, with an emphasis to elucidate the effects of reacting gas on the fabrication of diamond whiskers. Diamond whiskers were formed on diamond films pre-coated with Al. It was found that diamond whiskers preferentially formed at the diamond grain boundaries. The densities of diamond whiskers increased with O_2/Ar ratio. Whiskers obtained in pure O_2 plasma etching were 50 nm in diameter and 1 mu m in height. The etching rate was increased by mixing Ar with appropriate volume of O_2. Al coated on the diamond surface reacted with O_2 to form Al_2O_3, serving as mask to restrain the etching underneath. Raman spectroscopy measurement confirmed that the whiskers kept sp~3 diamond bonding structure after RF plasma etching. The field emission characteristics of the whiskers were also inspected.