Gas-Assisted Etching of Sapphire Using Focused Ion Beam

The etching parameters of ion beam current, beam overlap percentage and beam dwelling time for focused-ion-beam etching and gas-assisted focused-ion-beam etching on sapphire substrate have been investigated. The etching rate increases with gallium ion beam current for focused-ion-beam etching. The etching rate can be greatly enhanced using a xenon difluoride gas-assisted focused-ion-beam and a sharp depth profile can be obtained owing to less re-deposition and more efficient chemical etching. The etching rate of xenon difluoride gas-assisted focused-ion-beam etching decreases with beam overlap percentage and resulting beam dwelling time. These relationships could be due to the higher re-deposition rate that resulted from the higher etching rate of gas-assisted focused-ion-beam etching.