Inductively Coupled Plasma Etching of InP with Cl2/H2/Ar Plasma

The ability to fabricate high aspect ratio features in InP is crucial for the development of optoelectronic devices for applications such as deep ridge waveguides, ring resonators, and other optical communication devices in the 1.3-1.55 μm wavelength regime. These types of applications require anisotropic profiles with small sized features, while still obtaining smooth surface morphology. Dry etching of InP has been investigated in the past with Cl2, HBr, and CH4 –based plasma chemistries. While Cl2 – based plasma chemistries require the use of elevated electrode temperatures (>150 °C) in order to voltalize a greater amount of InClx, CH4 –based plasma chemistries results in low etch rates of typically ~100 nm/min or less 1. The effect of ICP power, RF power and the ratio of Cl2 to H2 is investigated on etch rate, sidewall morphology