III–V and Ge/strained SOI tunneling FET technologies for low power LSIs

We have demonstrated high performance operation of planar-type tunnel field-effect transistors (TFETs) using Ge/ III-V materials. Tensile strain in Si channels combined with the Ge source can enhance the tunneling current because of the reduced effective bandgap. The fabricated Ge/sSOI (1.1 %) TFETs show high I_on/I_off ratio over 10⁷ and steep minimum subthreshold slope (SS) of 28 mV/dec. It is found that I_on and SS are improved by positive back bias. We have also demonstrated the operation of high I_on/I_off and low SS planar-type InGaAs Tunnel FETs with Zn-diffused source junctions. Solid-phase Zn diffusion can realize steep-profile and defect-less p⁺/n source junctions. The small S.S. of 64 mV/dec and large I_on/I_off ratio over 10⁶ have been realized in the planar-type III-V TFETs.