Molecular beam epitaxial growth of metamorphic AlInSb/GaInSb high-electron-mobility-transistor structures on GaAs substrates for low power and high frequency applications

Abstract

We report on molecular beam epitaxial growth of AlInSb/GaInSb metamorphic high-electron-mobility-transistor structures for low power, high frequency applications on 4 in. GaAs substrates. The structures consist of a Ga0.4In0.6Sb channel embedded in Al0.4In0.6Sb barrier layers which are grown on top of an insulating metamorphic buffer, which is based on the linear exchange of Ga versus In and a subsequent exchange of As versus Sb. Precise control of group V fluxes and substrate temperature in the Al0.4In0.6As1−xSbx buffer is essential to achieve high quality device structures. Good morphological properties were achieved demonstrated by the appearance of crosshatching and root mean square roughness values of 2.0 nm. Buffer isolation is found to be >100 kΩ/◻ for optimized growth conditions. Hall measurements at room temperature reveal electron densities of 2.8×1012 cm−2 in the channel at mobility values of 21.000 cm2/V s for single-sided Te volume doping and 5.4×1012 cm−2 and 17.000 cm2/V s for double-sided Te δ-doping, respectively.