Photochemical fine etching using FIB-induced damage in GaAs for in-situ dry processing

Abstract

We have developed a new FIB maskless microfabrication process using photochemical dry etching. After n-type GaAs (1×10 18/cm 3) was irradiated by focused Be, Si, and Au ion beams, the sample was photochemically etched in HCl gas under a mercury lamp. The FIB-induced damage reduced the etching rate. 0.2 μm-wide fine patterns are successfully formed. The etching rate ratio between the ion implanted (1×10 13 ions/cm 2) and unimplanted regions is about 5. This dose is three or four orders of magnitude smaller than the dose for Cl 2 gas assisted FIB direct etching, and is comparable to the dose needed for organic resist exposure.