Electrical characteristics of AIO_xN_y prepared by oxidation of sub-10-nm-thick AIN films for MOS gate dielectric applications

In this research, the feasibility of ultrathin AlO_xN_y prepared by oxidation of sub 100-Å-thick AlN thin films for metal-oxide-semiconductor (MOS) gate dielectric applications was investigated. Oxidation of 51-Å- and 98-Å-thick as-deposited AlN at 800 °C was used to form 72-Å- and 130-Å-thick AlO_xN_y, respectively. Based on the capacitance-voltage (C-V) measurements of the MOS capacitor, the dielectric constants of 72 Å-thick and 130 Å-thick Al-oxynitride were 5.15 and 7, respectively. The leakage current of Al-oxynitride at low field was almost the same as that of thermal SiO₂. Based on the CV data, the interface state density of Al-oxynitride was relatively higher than that of SiO₂. Although process optimization is still necessary, the Al-oxynitride exhibits some possibility for future MOS gate dielectric applications.