The influence of an In$_{0.52}$Al$_{0.48}$As transition layer design on the transport characteristics of a metamorphic high-electron-mobility transistor

We have used the atomic force microscopy and Hall effect measurements to study the influence of In$_{0.52}$Al$_{0.48}$As transition layer design on the electron mobility in the InAlAs/InGaAs/GaAs channel of a highelectron- mobility transistor (HEMT) with the metamorphic buffer. The optimum buffer layer favors suppression of the misfit dislocation threading into upper layers of the HEMT heterostructure and prevents development of the surface microrelief.