Effects of post-deposition treatments on ultrathin nitride/oxide gate stack prepared by RTCVD for ULSI devices

Effects of post-treatments on ultrathin nitride/oxide stacks prepared by co mmercial rapid thermal CVD (RTCVD) cluster tools have been investigated. Tw o-step post-deposition treatments (i.e., NH3 nitridation followed by N2O an nealing) were performed at different temperatures to study their effects on dielectric integrity and electrical characteristics. And found that the ga te stack can be more stoichiometric, thinner equivalent oxide thickness (EO T) and significant reduction in leakage current simultaneously by increasin g NH3 nitridation temperature. But it suffered from slightly transconductan ce (G(m)) degradation due to incorporation of excess nitrogen. In addition, due to interfacial modification, the improved G(m) can be obtained by N2O annealing. However, N2O annealing step also results in increasing EOT and d egradation in gate current characteristics. (C) 2001 Elsevier Science Ltd. All rights reserved.