Demonstration of phase-controlled Ni-FUSI CMOSFETs employing SiON dielectrics capped with sub-monolayer ALD HfSiON for low power applications

摘要

In this work, by employing a sub-monolayer HfSiON cap (via ALD deposition) on the SiON host dielectrics in the phase-controlled Ni-FUSI CMOS devices, we report that 1) the devices (both n-FETs and p-FETs) V_t is effectively modulated likely due to the Fermi-level pinning relaxation; 2) the gate leakage is significantly reduced; 3) the dielectrics reliability characteristics (such as TZBD, pFETs NBTI, and nFETs PBTI) are clearly improved; 4) both the gate capacitance equivalent thickness (T_(inv)) and the long channel device high E_(eff) mobility are preserved. High-V-t ring oscillator with a delay of 17ps has been demonstrated, showing a much-reduced static power (～10 times) as compared to the devices using the pure SiON dielectrics. It is proposed that the SiON dielectrics capped with sub-monolayer HfSiON, in combination with the phase-controlled Ni-FUSI technology, is promising for 45nm and beyond low power CMOS applications.