ULTRATHIN SIOXNY BY RAPID THERMAL HEATING OF SILICON IN N-2 AT T=760-1050-DEGREES-C

In this letter, we report on the reaction between Si and N-2 in the te mperature range of 760-1050 degrees C, in a rapid thermal processing c hamber, Gas phase impurities such as H2O, O-2, and H-2, which can outg as from the cold walls of the chamber, mediate the Si/N-2 reaction, re sulting in the formation of SiOxNy. The oxynitridation can be explaine d by equilibrium chemical thermodynamics, in contrast to the case of o xynitridation using N2O or NO, where the nitrogen is incorporated unde r nonequilibrium conditions. Using nuclear reaction analysis, we have measured nitrogen contents as high as 2.5 x 10(15) N/cm(2) (the equiva lent of more than 3 monolayers) in these new dielectrics. They can be reoxidized to form ultrathin 42 to 3 nm) dielectrics. (C) 1997 America n Institute of Physics.