IMPROVED PERFORMANCE OF HIGHLY STRAINED INGAAS/GAAS HETEROSTRUCTURE DEVICES GROWN ON PATTERNED GAAS SUBSTRATES

Al0.15Ga0.85As/In0.25Ga0.75As pseudomorphic modulation-doped field-effect transistors and strained InxGa1-xAs/GaAs p-i-n photodiodes have been fabricated on patterned (100)-GaAs substrates and characterized. Compared with devices made on planar substrates, small area growth improves the dc transconductance by 40% and current gain cutoff frequency by 50% in the transistors. The photodiodes grown in small recesses (approximately 30-mu-m) exhibit 2-4 times higher quantum efficiency than those grown on planar substrates.