In situ SIMS monitoring for ion beam etching of III-V semiconductor compounds and metal contacts

Experimental results with a secondary ion mass spectroscopy in situ monitoring system for ion beam etching are described. The authors demonstrate that the sensitivity of this method is high enough to monitor the dry etching of any type of semiconductor material in the InP/InGaAsP and GaAs/AlAs basis with both the commonly used etch gases, N2 and Ar. The technique enables the precise control of metal contact dry etching. Layers of a thickness as low as 2.5 nm for a minimum etched surface of only 15 mm2 were resolved.