ALD HfO/sub 2/ using heavy water (D/sub 2/O) for improved MOSFET stability

Abstract

Device instability is one of the most challenging issues to implement high-k gate dielectrics. Incorporation of deuterium during the ALD (atomic layer deposition) process effectively improves the interface quality that enhances high-k device stability and reliability. Compared to H/sub 2/O processed HfO/sub 2/ devices, devices with D/sub 2/O processing result in a significantly smaller Vt shift after constant voltage stressing at room temperature and at 125/spl deg/C under NBTI/PBTI conditions, as well as a longer CHCI lifetime. This process is independent of transistor process integration and is relatively low cost. It has the potential to become an industry standard if ALD high-k gate dielectric processing is the final choice.