Effects of N2 and NH3 remote plasma nitridation on the structural and electrical characteristics of the HfO2 gate dielectrics

The remote plasma nitridation (RPN) of an HfO2 film using N2 and NH3 has been investigated comparatively. X-ray photoelectron spectroscopy and Auger electron spectroscopy analyses after post-deposition annealing (PDA) at 700 °C show that a large amount of nitrogen is present in the bulk film as well as in the interfacial layer for the HfO2 film nitrided with NH3-RPN. It is also shown that the interfacial layer formed during RPN and PDA is a nitrogen-rich Hf–silicate. The C–V characteristics of an HfOxNy gate dielectric nitrided with NH3-RPN have a smaller equivalent oxide thickness than that nitrided with N2-RPN in spite of its thicker interfacial layer.