Reliability investigation of ultrathin oxides grown by high pressure oxidation and nitrided in N/sub 2/O 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 /spl Aring/ thick HIPOX oxide nitrided at 1100/spl deg/C for 30 sec, the lifetime of the nitrided-HIPOX oxide at negative constant current stress, -1.0/spl times/10/sup -6/ A/cm/sup 2/ is about 1.2/spl times/10/sup 9/ sec. Initially, the midgap interface trap density (D/sub itm/) of 75 /spl Aring/ thick nitrided-HIPOX oxide is about 2.0/spl times/10/sup 10/ cm/sup -2//spl middot/eV/sup -1/ which is comparable to that of control oxide grown by conventional thermal oxidation. The /spl Delta/D/sub itm/ of the nitrided-HIPOX oxide subjected to the stressing time of 1/spl times/10/sup 4/ sec under -0.1 A/cm/sup 2/ is 1.1/spl times/10/sup 11/ cm/sup -2//spl middot/eV/sup -1/ which is lower than that (1.5/spl times/10/sup 11/ cm/sup -2//spl middot/eV/sup -1/) of the control oxide under the same stressing condition.