Molecular beam epitaxy growth of InAs and In[sub 0.8]Ga[sub 0.2]As channel materials on GaAs substrate for metal oxide semiconductor field effect transistor applications

Abstract

InAs and high indium concentration InGaAs have very high electron mobilities and saturation velocities. Using them as the metal oxide semiconductor field effect transistor (MOSFET) channel materials is a very promising way to keep improving the integrated circuit chip performance beyond Moore’s law. One major obstacle is the growth of these high mobility channel materials on lattice-mismatched substratcs. In this work, we studied the molecular beam epitaxy growth of InAs, In0.8Al0.2As, and In0.8Ga0.2As on lattice-mismatched GaAs substrate using a thin indium-rich InAs wetting layer. Reflection high energy electron diffraction and atomic force microscopy were used to optimize the growth conditions. A surface roughness of ∼0.5nm rms was obtained for InAs layers. A new MOSFET structure with In0.8Ga0.2As channel and In0.8Al0.2As buffer layer was also demonstrated. High mobility depletion mode MOSFET characteristics were demonstrated.