FABRICATION OF DRY-ETCHED MIRRORS FOR IN0.20GA0.80AS GAAS WAVE-GUIDESUSING AN ELECTRON-CYCLOTRON-RESONANCE SOURCE/

High quality In(0.20)Ga(0.80)AS/GaAs total internal reflecting mirrors have been demonstrated. The miners were fabricated by dry etching usi ng a Cl-2/Ar plasma generated with an electron cyclotron resonance sou rce. The etched mirrors have smooth sidewalls and vertical profile. Mi rror reflectivities up to 93% have been measured. The mirror reflectiv ity has been studied as a function of etch conditions including ion en ergy and ion flux. The effects of etch profile on reflectivity were al so investigated. It was found that the reflectivity of the etched mirr ors was not sensitive to either the ion energy or the ion flux used fo r the etching. As long as a vertical profile and smooth surface morpho logy are maintained, the reflectivity remains at similar to 90% even w hen high radio-frequency power (200 W) and high microwave power (150 W ) were used for etching. However, significant degradation of the mirro r reflectivity to only 47% was found on mirrors with a slight undercut profile and rougher sidewalls. The results suggest that mirror reflec tivity is much more sensitive to etch profile. Triangular ring lasers with etched mirrors were also fabricated, and threshold current as low as 3.7 mA has been demonstrated, showing the high quality of the etch ed mirrors. (C) 1995 American Vacuum Society.