UNIFORM DURABLE THIN DIELECTRICS PREPARED BY RAPID THERMAL-PROCESSINGIN AN N2O AMBIENT

Thin dielectrics were grown on silicon wafers by rapid thermal process ing in an N2O ambient at temperatures of 1100-degrees-C, 1150-degrees- C, and 1200-degrees-C. The resulting films, in conjunction with an O2 ambient control, were characterized by thickness measurements and elec trical performance. Dielectrics formed in N2O in this temperature rang e were all superior to that prepared in an O2 ambient in terms of inte rface state generation and flatband voltage shift after constant curre nt stressing. Although all N2O prepared samples exhibited similar cros s wafer electrical uniformity, higher growth temperature favored thick ness uniformity. The electrical behavior of the N2O wafers was not str ongly dependent on growth temperature, however a 60-s 1100-degrees-C p ost-oxynitridation N2 anneal was found to significantly reduce subsequ ent electrical performance. It is also demonstrated that under optimum process conditions, high-quality uniform dielectrics can be formed by RTP in N2O.