Germanium N and P Multifin Field-Effect Transistors With High-Performance Germanium (Ge) p(+)/n and n(+)/p Heterojunctions Formed on Si Substrate

Abstract

We demonstrate the characteristics of p(+)-Ge/n-Si and n(+)-Ge/p-Si heterojunction diodes formed by heteroepitaxial Ge grown on Si leading to high performance and very low leakage current. The ON/OFF current ratio of the p(+)-Ge/n-Si and n(+)-Ge/p-Si heterojunction was >10(7) and >10(6), respectively. The OFF current density was extremely low at <10 mu A/cm(2) for the p(+)-Ge/n-Si formed with different implantation energies of 10 similar to 40 KeV and similar to 20 mu A/cm(2) for the n(+)-Ge/p-Si with different implantation energies of 20 similar to 50 KeV at a reverse bias of vertical bar V-R vertical bar = +/- 1 V, respectively. Both p and n-Ge channel multifin field-effect transistors (FinFETs) were formed by a mesa structure using these p(+)-Ge/n-Si and n(+)-Ge/p-Si heterojunctions. A high-kappa/metal gate stack was employed. The body-tied Ge multifin FinFET with a fin width (W-Fin) of similar to 40 nm, and the channel length (L-Channel) was 150 nm for p-FinFET and of 110 nm for n-FinFET, exhibiting a driving current of 174 mu A/mu m at V-G = -2 V and 102 mu A/mu m at V-G = 2 V, respectively. This is the first experimental demonstration of a body-tied high mobility Ge channel multifin FinFET using a top-down approach.