Nitrous oxide gas phase chemistry during silicon oxynitride film growth

Abstract

N 2O gas phase chemistry has been examined as it relates to the problem of ultrathin film silicon oxynitridation for semiconductor devices. Computational and analytical kinetics studies are presented that demonstrate: (i) there are 5 main reactions in the decomposition of N 2O, (ii) the gas composition over a 1000K – 1400K temperature range is as follows: N 2 (65.3 − 59.3%); O 2 (32.0 − 25.7%); NO (2.7 − 15.0%), (iii) the N 2O decomposition obeys first-order kinetics, and the initial rate law for N 2O decomposition is R init = 2k 1[N 2O] which rapidly changes to R late = k 1[N 2O] as the reaction proceeds, (iv) the branching ratio for the two reactions: N 2O + O → 2NO and N 2O + O → N 2 + O 2 lies between 0.1 and 0.5 (0.1 < α < 0.5) and varies with conditions, (v) the apparent activation energy for the decomposition of N 2O is 2.5 eV/molecule (2.4×10 2 kJ/mole), (vi) the rate law for NO formation is R = k 1N 2O], and (vii) the apparent activation energy for the formation of NO is 2.4 eV/molecule (2.3×10 2 kJ/mole).