Novel method to determine the band offset in hetero staggered bandgap TFET using Esaki diodes

Summary form only given. In heterojunction Tunneling Field-Effect Transistors (TFET), the effective tunneling bandgap (E_g,eff) has a strong impact on the on-current (I_on) and the subthreshold swing (SS) (figure 1). There is however significant uncertainty on E_g,eff for the staggered heterojunction In_0.53Ga_0.47As/GaAs_0.50Sb_0.50 (InGaAs/GaAsSb), with values in literature ranging from 0.5 eV to 0.27 eV [3-6]. An additional problem is that E_g,eff is usually measured optically on lowly doped heterojunctions [7-8]. These values may be far off for use in TFETs where there is bandgap narrowing due to heavy doping (doping-BGN) in the source and pocket regions. The impact of doping-BGN on Band-To-Band Tunneling (BTBT) is currently not well understood, contributing to the difficulty in making quantitative hetero-TFET predictions.