Electrical and optical characteristics of etch induced damage in InGaAs

The effects of etch induced damage on the electrical and optical properties of AlGaAs/InGaAs quantum wells (QWs) were studied. From the variations in the photoluminescence (PL) intensity and the conductivity of etched grating s, the optical cutoff width was found to be 33 nm whereas the electrical cu toff width was 136 nm. The PL intensity of the gratings indicated that incr eased stage power during etching causes more damage. Comparisons were also made between the sheet resistivity (rho(s)) of transmission lines and the c onductivity of wires after etching of AlGaAs/InGaAs and AlInAs/InGaAs QWs g rown on GaAs and InP substrates, respectively. The AlGaAs/InGaAs QW transmi ssion lines showed reduced rho(s) after etching with higher stage power, al though the rho(s) was still higher than that of the unetched control sample . The AlInAs/InGaAs QW transmission lines had a higher rho(s) as the stage power was increased. The two material systems also showed different etch ti me and sidewall damage characteristics. The AlInAs/InGaAs QW structure degr aded more severely at a shorter etch time and had a larger cutoff width as extracted from etched conducting wires. (C) 1998 American Vacuum Society.