Electrical Characterization of Aluminum-Oxynitride Stacked Gate Dielectrics Prepared by a Layer-by-Layer Process of Chemical Vapor Deposition and Rapid Thermal Nitridation

Abstract

We investigated the use of AlO x :N/SiN y stacked gate dielectric as an alternate gate dielectric, which were prepared by alternately repeating sub-nanometer deposition of Al 2 O 3 from an alkylamine-stabilized AlH 3 + N 2 O gas mixture and rapid thermal nitridation in NH 3 . The negative fix charges, being characteristics of almina, were as many as 3.9 x 10 12 cm -2 in the effective net charge density. The effective dielectric constant and the breakdown field were 8.9 and 8 MV/cm, respectively, being almost the same as pure Al 2 O 3 . And we have demonstrated that the leakage current through the AlO x :N/SiN y stacked gate dielectric with a capacitance equivalent thickness (CET) of 1.9 nm is about two or ders of magnitude less than that of thermally-grown SiO 2 . Also, we have confirmed the dielectric degradation similar to the stress-induced leakage current (SILC) mode and subsequent soft breakdown (SBD) reported in ultrathin SiO 2 under constant current stress and a good dielectric reliability comparable to thermally-grown ultrahin SiO 2 . From the analysis of npoly-Si gate metal-insulator-semiconductor field effect transistor (MISFET) performance, remote coulomb scattering due to changes in the gate dielectric plays an important role on the mobility degradation of MISFET with AlON/SiON gate stack.