In this paper we first report an exothermic phenomenon of silicon oxidation by N2O. This phenomenon results from the decomposition of N2O at high temperature. The heat generated by introducing N2O increases the furnace temperature during the oxidation process and results in an increased oxide thickness. To control temperature well, we developed a two–table profiling technique to obtain a more stable processing temperature. We also found the growth kinetic of N2O decomposed into N2 and O2 is similar to dilute O2(10%)/Ar.