Structural, morphological, and defect properties of metamorphic In0.7Ga0.3As/GaAs0.35Sb0.65 p-type tunnel field effect transistor structure grown by molecular beam epitaxy

Abstract

Structural properties of metamorphic In0.7Ga0.3As/GaAs0.35Sb0.65 p-type tunnel field effect transistor (TFET) structure grown by molecular beam epitaxy were comprehensively investigated. High resolution x-ray diffraction revealed symmetric strain relaxation and pseudomorphic In0.7Ga0.3As/GaAs0.35Sb0.65 active layers with respect to the In0.7Al0.3As buffer, indicating a low dislocation density within the active region. The surface morphology of this structure exhibited a typical two-dimensional cross-hatch pattern with a low root-mean-square roughness of 2.58 nm. Cross-sectional transmission electron microscopy demonstrated a low threading dislocation density within the active region, suggesting high crystalline quality of this p-type TFET structure. Dynamic secondary ion mass spectrometry exhibited an abrupt doping profile over the In0.7Ga0.3As/GaAs0.35Sb0.65 source/channel junction as well as minimal level of intermixing between As and Sb atoms. Thus, these structural properties showed high quality of this structure and provided critical guidance for the fabrication of As/Sb based staggered gap complementary TFETs for ultra-low standby power and energy efficient logic applications.