Study of Bias-Temperature Instability in HfO2 sputtered Thin Films by Post Nitrogen Annealing for the Advanced CMOS Technology

Abstract

This paper presents a study on Negative bias temperature instability (NBTI) on high-k HfO2 sputtered thin films annealed in oxygen and nitrogen ambient. Activation energies for interface, oxide-trap charge and switching states densities for each oxygen and nitrogen ambient annealed devices is estimated from capacitance-voltage measurements versus temperature characteristics. It is found in the range 0.13eV-0.16eV for oxygen annealed sample and 0.47eV – 0.7eV for nitrogen annealed sample. Nitrogen annealed sample shows higher activation energy and low traps charge densities.