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Many in the microelectronics field view tunneling field-effect transistors (TFETs) as society's best hope for achieving a >10× power reduction for electronic devices; however, despite a decade of considerable worldwide research, experimental TFET results have significantly underperformed simulations and conventional MOSFETs. To explain the discrepancy between TFET experiments and simulations, we investigate the parasitic leakage current due to Auger generation, an intrinsic mechanism that cannot be mitigated with improved material quality or better device processing. We expose the intrinsic link between the Auger and band-to-band tunneling rates, highlighting the difficulty of increasing one without the other. From this link, we show that Auger generation imposes a fundamental limit on ultimate TFET performance. [ABSTRACT FROM AUTHOR]

Band-to-band tunneling was studied in ion-implanted P/N junction diodes with profiles representative of present and future silicon complementary metal-oxide-silicon (CMOS) field effect transistors. Measurements were done over a wide range of temperatures and implant parameters. Profile parameters were derived from analysis of capacitance versus voltage characteristics, and compared to secondary-ion mass spectroscopy analysis. When the tunneling current was plotted against the effective tunneling distance (tunneling distance corrected for band curvature) a quasi-universal exponential reduction of tunneling current versus, tunneling distance was found with an attenuation length of 0.38 nm, corresponding to a tunneling effective mass of 0.29 times the free electron mass (m 0), and an extrapolated tunneling current at zero tunnel distance of 5.3× 10 7 A/cm² at 300 K. These results are directly applicable for predicting drain to substrate currents in CMOS transistors on bulk silicon, and body currents in CMOS transistors in silicon-on-insulator. [ABSTRACT FROM AUTHOR]

The electrical characteristics of a heterojunction tunneling field-effect transistor (HETT), with a p-type \Si0.75\Ge0.25 source, have been measured as a function of strain. HETTs with channel transport and applied strain both in the [110] direction show a smooth monotonic change in drain current over a range of 0.09% compressive to 0.13% tensile strain. A measure \gamma = (d/d\ln JD)(d\ln JD/ds)\verts = 0 of the effect of strain s on tunneling current JD is proposed, which captures the dependence of the tunneling exponential argument on strain. An experimental value of \gamma = - \11.7 is extracted for the tensile case and compared to simulation results. We found theoretically that the value and sign of \gamma depend sensitively on the built-in strain at the Si–SiGe interface. [ABSTRACT FROM AUTHOR]

A simple potential mapping is used to show that tunneling through a single barrier, as in Schottky-barrier tunneling or source-to-drain tunneling in MOSFETs, cannot give rise to subthreshold swings below the thermionic limit (60 mV/decade at room temperature). While cognizant of the difficulty of proving a negative, it is thus highly unlikely that Schottky-barrier tunneling alone can result in reported instances of subthreshold swings that are less than 60 mV/decade. [ABSTRACT FROM AUTHOR]