HIGH-RATE DRY-ETCHING OF INGAP IN BCL3 PLASMA CHEMISTRIES

A remarkable increase in InGaP etch rate in electron cyclotron resonan ce BCl3 discharges is observed as the microwave power is increased fro m 250 W (etch rate similar to 500 Angstrom/min) to 1000 W (etch rate s imilar to 8000 Angstrom/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 fo rmation of the nonstoichiometric In-rich surfaces generally observed w ith Cl-2-based dry etching using conventional reactive ion etching. (C ) 1995 American Institute of Physics.