High Resistivity AlGaAs Grown by Low Temperature MBE

Al$\text{}_{0.3}$Ga$\text{}_{0.7}$As layers were grown by molecular beam epitaxy using substrate temperature 200-300°C, tetrameric As and two values of As/Ga+Al flux ratio i.e. 3 or 8. The post-growth annealing was performed in situ at 600°C for 20 min under As-overpressure. The samples were characterised by reflection high-energy electron diffraction, transmission electron microscope and room-temperature I-V measurements of n$\text{}^{+}$/LT grown layer /n$\text{}^{+}$ resistors. The resistivity and trap-filled limited voltage have been determined. The best layers exhibited ρ of the order of 10$\text{}^{9}$ Ω cm, were monocrystalline, uniformly precipitated and without dislocations.