Improving the on-current of $In0.7Ga0.3As$ tunneling field-effect-transistors by $p++/n+$ tunneling junction

We have compared the device performance of $In0.7Ga0.3As$ $HfO2$ gate dielectric tunneling field-effect-transistors (TFETs) using $p++/i$ or $p++/n+$ tunneling junctions. Devices with $p++/n+$ tunneling junctions show 61% and 20% higher current at $Vg-Vth=0.5$ and 2 V compared to the ones with $p++/i$ junctions. These $p++/n+$ TFETs exhibit an on-current of $60μA/μm$ and a minimum subthreshold swing of 84 mV/dec. Device characteristics of TFETs using $p++/n+$ tunneling diodes with various $n+$ region doping concentrations have been simulated, results indicate the doping concentration of the $n+$ region plays an important role in determining the on-current and providing a well gate-controlled tunneling behavior.