Staggered band gap n+In0.5Ga0.5As/p+GaAs0.5Sb0.5 Esaki diode investigations for TFET device predictions

• Influence of MBE growth conditions on GaAsSb composition.
• High quality InGaAs(Si)/GaAsSb(Be) diodes for sub-60mV/dec operating devices.
• x60 BTBT current density improvement using n+InGaAs/p+GaAsSb compared to n+/p+InGaAs.

We study in this paper the epitaxial growth and electrical characterization of an n+In0.5Ga0.5As/p+GaAs0.5Sb0.5 Esaki diode lattice matched to (001)-oriented InP substrate. First, the effects of molecular beam epitaxy growth temperature and group-V growth rates on the GaAsxSb1−x composition are characterized by means of X-ray diffraction (XRD). It is found that GaAsxSb1−x lattice constant is mainly determined by the Sb4 incorporation rather than the As4 one. After optimization, high quality In0.54Ga0.46As(Si)/GaAs0.52Sb0.48(Be) heterostructure is confirmed by XRD, Transmission electron microscope (TEM) and Secondary Ion Mass Spectroscopy (SIMS) profiles meeting requirements for sub-60 mV/dec operating devices. Esaki tunnel diodes are then fabricated to be used as a prediction of Band-To-Band Tunneling (BTBT) for Tunnel Field-Effect transistors (TFETs). The results are compared to previously reported n+/p+In0.5Ga0.5As homojunction diodes, showing a ×60 factor improvement of BTBT current density for the same electric field with an excellent average Peak-to-Valley Current Ratio (PVCR) of 14.