NEW HIGH-RATE DRY ETCH MIXTURE FOR INP-BASED HETEROSTRUCTURES

A dry etch mixture based on HI/H-2 is shown to provide smooth, equirate removal of InP and InGaAsP at rates of approximately 2000 angstrom min-1 even for very low (-100 V) DC biases on the sample. This is significantly faster than the rates obtained with the more conventional CH4/H-2 mixtures commonly used for dry etching of InP-based heterostructures. Metal masks (Ni, Pt, Mo, Ti and Al) show minimal erosion during exposure to HI/H-2 discharges, and other common masking materials (Au, SiO2 and SiN) also show very low removal rates (< 20 angstrom min-1) for low (less-than-or-equal-to 200 V) DC biases on the sample.