Low-Threshold-Voltage HfO_xN p-Channel Metal–Oxide–Semiconductor Field-Effect Transistors with Partially Silicided Platinum Gate Electrode

HfO_xN p-channel metal–oxide–semiconductor field-effect transistors (MOSFETs) with a low threshold voltage (|V_th|) were successfully fabricated using a partially silicided (PASI) platinum gate electrode for scaled complementary MOS (CMOS). The PASI platinum (PASI-PtSi) gate electrode is composed of a monoclinic-Pt₃Si phase in the vicinity of a HfO_xN dielectric. The reduced silicon content of the PASI gate electrodes is effective in suppressing the Fermi-level pinning on the Hf-based gate dielectrics which induces a significant |V_th| shift in p-channel MOSFETs. It is shown that the |V_th| of HfO_xN p-channel MOSFETs with the PASI-PtSi gate electrode is sufficiently low and applicable to low-standby-power devices. The mobility of the holes at 0.8 MV/cm is as high as about 90% of the universal mobility. It is concluded that the PASI technology in which the gate electrode has a reduced silicon content is useful for scaled CMOSs.