AN OPTIMIZED 850-DEGREES-C LOW-PRESSURE-FURNACE REOXIDIZED NITRIDED OXIDE (ROXNOX) PROCESS

The electrical characteristics of thin (10 nm) MOS gate dielectrics formed at 850-degrees-C by low-pressure furnace nitridation of SiO2 followed by an oxygen anneal (reoxidation) are described. Previously, low-pressure reoxidized nitrided oxide (ROXNOX) dielectrics formed at 950-degrees-C have been shown to: i) reduce interface state generation and electron trapping under electrical stress [1], and ii) eliminate interface state generation and reduce positive charge buildup under radiation stress [2], as compared to conventional oxide. In this work, the ROXNOX process is demonstrated to be readily scalable from 950-degrees-C to 850-degrees-C through the use of higher partial pressures in the nitridation and reoxidation steps, resulting in the same quality dielectric formed with a lower Dt product. Electrical characterization results of capacitors and transistors with the 850-degrees-C ROXNOX dielectric are presented. Reliability of the 850-degrees-C ROXNOX dielectric is demonstrated through Fowler-Nordheim and channel hot-electron stressing results.