Reliability characteristics and surface preparation technique for ultra-thin (33 /spl Aring/-87 /spl Aring/) oxides and oxynitrides

Surface preparation, dielectric breakdown and stress-induced leakage current effects are some of the most Important issues for ultrathin dielectric processes. In this paper, a novel "two-step dip" wafer-cleaning procedure is proposed for ultra-thin dielectric growth. Improved dielectric integrity has been observed for ultra-thin thermal oxides and N/sub 2/O oxynitrides fabricated using this surface preparation technique. Dielectric breakdown mechanism for the ultra-thin N/sub 2/O oxynitrides was also investigated in this study. It was found that holes generated within the dielectrics were responsible for the catastrophic breakdown for both thermal oxides and N/sub 2/O oxynitrides within the thickness range studied (33-87 /spl Aring/). In addition, stress-induced leakage current (SILC) does not monotonically increase when the dielectrics are aggressively scaled down to the ultra-thin regime. This "turn-around" effect of SILC can be explained using the trap-assisted tunneling model.<>