Large On-Current Enhancement in Hetero-Junction Tunnel-FETs via Molar Fraction Grading

We propose to employ a grading of the molar fraction in the source region of III-V hetero-junction tunnel-FETs as a means to improve the on-current without degrading the subthreshold swing. Our full quantum simulations show that the molar-fraction grading increases the on-current by enlarging the hole wave function penetration from the source to the channel region. We also compare the performance of graded AlGaSb/InAs tunnel FETs and InAs MOSFETs and show that at V_DS=0.3 V, the tunnel device can outperform the MOSFET in terms of both on-current and subthreshold slope.