Improved current performance of CMOSFETs with nitrogen incorporated HfO₂-Al₂O₃ laminate gate dielectric

For the first time, we integrated poly-Si gate CMOSFETs with nitrogen incorporated HfO₂-Al₂O₃ laminate (HfAlON) as gate dielectrics. Both low gate leakage currents (0.1mA/cm² at V_g=+1.0V) and low EOT (15.6 Å) sufficiently satisfy the specifications (EOT=12∼20Å, J_g=2.2mA/cm²) estimated by ITRS for low power applications. By in-situ 3 step post-deposition annealing, approximately 17 at.% nitrogen is incorporated at the HfAlON/Si interface. In-situ 3 step post-deposition annealing decreases metallic Hf bonding, which exists at the HfO₂-Al₂O₃ laminate/Si interface. As a result, we can suppress C-V hysteresis and improve current performance. Finally, well-behaved 100 nm CMOSFET devices are achieved. The measured saturation currents at 1.2V Vdd are 585μA/μm (I_off=10nA/μm) for nMOSFET and 265μA/μm (I_off=10nA/ μm) for pMOSFET, which are approximately 80% of those of nitrided SiO₂. In terms of I_on-I_off characteristics of n/pMOSFETs, these are the best current performance compared with previous reports for the poly-Si gate CMOSFETs with high-k gate dielectrics.