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

摘要

We demonstrate the characteristics of ${{rm p}}^{+}$-Ge-Si and ${{rm n}}^{+}$-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 ${rm p}^{+}$-Ge-Si and ${rm n}^{+}$-Ge/p-Si heterojunction was ${>}{10^{7}}$ and ${>}{10^{6}}$, respectively. The OFF current density was extremely low at ${<}{rm 10}~mu{rm A}/{rm cm}^{2}$ for the ${rm p}^{+}$-Ge-Si formed with different implantation energies of 10–40 KeV and ${sim}{rm 20}~mu{rm A}/{rm cm}^{2}$ for the ${rm n}^{+}$-Ge/p-Si with different implantation energies of 20–50 KeV at a reverse bias of $vert V_{rm R}vert=pm1~{rm V}$ , respectively. Both p and n-Ge channel multifin field-effect transistors (FinFETs) were formed by a mesa structure using these ${rm p}^{+}$-Ge-Si and ${rm n}^{+}$-Ge/p-Si heterojunctions. A high-$kappa$/metal gate stack was employed. The body-tied Ge multifin FinFET with a fin width $({W}_{rm Fin})$ of ${sim}{rm 40}~{rm nm}$, and the channel length $({rm L}_{rm Channel})$ was 150 nm for p-FinFET and of 110 nm for n-FinFET, exhibiting a driving current of 174 $mu{rm A}/mu{rm m}$ at $V_{rm G}=-2~{rm V}$ and 102 $mu{rm A}/mu{rm m}$ at $V_{rm G}=2~{rm V}$ , respectively. This is the first experimental demonstration of a body-tied high mobility Ge channel multifin FinFET using a top-down approach.