Publication

Abstract : It is well known that Hf-based dielectrics have replaced the traditional SiO 2 and SiON as gate dielectric materials for conventional CMOS devices. By using thicker high-k materials such as HfO 2 rather than ultra-thin SiO2, we can bring down leakage current densities in MOS devices to acceptable levels. HfO 2 is also one of the potential candidates as a blocking dielectric for Flash memory applications for the same reason. In this study, effects of substrate heating and oxygen flow rate while depositing HfO 2 thin films using CVD and effects of post deposition annealing on the physical and electrical characteristics of HfO 2 thin films are presented. It was observed that substrate heating during deposition helps improve the density and electrical characteristics of the films. At higher substrate temperature, V fb moved closer to zero and also resulted in significant reduction in hysteresis. Higher O 2 flow rates may improve capacitance, but also results in slightly higher leakage. The effect of PDA depended on film thickness and O 2 PDA improved characteristics only for thick films. For thinner films forming gas anneal resulted in better electrical characteristics.