Reliability investigation of ultrathin oxides grown by high pressure oxidation and nitrided in N2O for ULSI device applications

The reliability of new ultrathin oxides grown by high pressure oxidation (HIPOX) has been evaluated in order to use gate insulators for ULSI MOSFETs. From the results of the TDDB characteristics of 75 Å thick HIPOX oxide nitrided at 1100°C for 30 sec, the lifetime of the nitrided-HIPOX oxide at negative constant current stress, -1.0×10 ^-6 A/cm² is about 1.2×10⁹ sec. Initially, the midgap interface trap density (D_itm) of 75 Å thick nitrided-HIPOX oxide is about 2.0×10¹⁰ cm ^-2·eV^-1 which is comparable to that of control oxide grown by conventional thermal oxidation. The ΔD_itm of the nitrided-HIPOX oxide subjected to the stressing time of 1×10⁴ sec under -0.1 A/cm² is 1.1×10¹¹ cm^-2·eV^-1 which is lower than that (1.5×10¹¹ cm^-2·eV^-1) of the control oxide under the same stressing condition