DEVICE-QUALITY ALGAAS GROWN BY CHEMICAL BEAM EPITAXY

Device quality AlGaAs layers have been grown by CBE using both TMAA an d DMEAA on 3 inch diameter GaAs substrates. Al0.3Ga0.7As layers with o xygen concentrations as low as 1 x 10(16) cm(-3) have been obtained fo r undoped layers using aluminum sources from different suppliers. Low oxygen levels (< 5 x 10(16) cm(-3)) have also been achieved for Sn- an d carbon-doped AlGaAs. High power 980 nm InGaAs quantum well lasers ha ve been prepared with efficiencies as high as 1.0 W/A and thresholds c omparable to the best values obtained for MBE or MOCVD grown material. CBE grown heterojunction bipolar transistor structures have been proc essed into digital ICs that operate to speeds above 10 Gb/s. These dev ices show current gains of 50 to 80 for HBTs with base sheet resistanc es of 250 Omega/rectangle The low surface defect densities (< 10 cm(-2 ) for defects larger than 0.5 mu m) that are obtainable in the CBE pro cess present a clear advantage for device manufacturing. A simple meta lorganic cell design for the alanes is described that leads to reprodu cible and uniform alloy compositions.