High rate dry etching of InGaP in BCl3 plasma chemistries

Abstract

A remarkable increase in InGaP etch rate in electron cyclotron resonance BCl3 discharges is observed as the microwave power is increased from 250 W (etch rate ∼500 Å/min) to 1000 W (etch rate ∼8000 Å/min). The surface roughness measured by atomic force microscopy decreases from 36 nm at 250 W to 2 nm at 1000 W. The high ion flux incident on the InGaP at high microwave powers appears to remove InClx species by sputter-assisted desorption and prevents formation of the nonstoichiometric In-rich surfaces generally observed with Cl2-based dry etching using conventional reactive ion etching.