Calibration of the Effective Tunneling Bandgap in GaAsSb/InGaAs for Improved TFET Performance Prediction.

The effective bandgap for heterojunction band-to-band tunneling ( $ {{E}}_{{\text {g,eff}}}$ ) is a crucial design parameter for a heterojunction tunneling FET (TFET). However, there is significant uncertainty on $ {{E}}_{{\text {g,eff}}}$ , especially for In0.53Ga0.47As/ GaAs0.5Sb0.5. This makes the prediction of TFET performance difficult. We calibrate $ {{E}}_{{\text {g,eff}}}$ by fabricating heterojunction p+/i/n+ diodes, comparing the simulated and the measured current–voltage and capacitance–voltage curves, while taking $ {{E}}_{{\text {g,eff}}}$ as a fitting parameter. Our calibration significantly reduces the uncertainty on $ {{E}}_{{\text {g,eff}}}$ compared with the range found in the literature. The comparison with the previous work on highly doped heterojunction diodes suggests that dopant-dependent bandgap narrowing reduces $ {{E}}_{{\text {g,eff}}}$ and therefore significantly impacts the performance of highly doped TFET. [ABSTRACT FROM AUTHOR]