Analysis of the transition layer in silicon nitride films deposited by a low-pressure chemical vapour deposition

A silicon nitride film was deposited on an Si(100) substrate with a silicon dioxide surface layer from NH3, and SLH2Cl2 by low-pressure chemical vapou r deposition under various conditions. The etching rates of the silicon nit ride films by buffered hydrofluoric acid (BHF) were investigated using Ruth erford backscattering spectroscopy. The change of the etching rate at the i nterface region suggested the existence of a transition layer on the interf ace between the silicon nitride film and the silicon dioxide layer on the s ubstrate. The silicon concentration of the transition layer is higher than that of the silicon nitride, The existence of a transition layer was also c onfirmed by angular-resolved XPS, Measurement of the etching rate of the si licon nitride films by BHF was applied to clarify the relation between the deposition conditions of the silicon nitride films and the thickness of the transition layer, The growth of the transition layer was controlled by nit ridation of the substrate in ammonia ambient before deposition of the silic on nitride film. Copyright (C) 1999 John Wiley & Sons, Ltd.