Silicon dots/clusters in silicon nitride: photoluminescence and electron spin resonance

Photoluminescence (PL) properties of SiNx (0.51 < x < 1.3) films are studie d. A visible luminescence near the UV region is observed and the PL intensi ty and peak positions are found to be governed by the excess silicon compos ition. A large scale potential fluctuation due to the spatial variation of chemical composition in SINx is proposed to explain these observations, In addition, non-radiative recombination centers (N3Si ., N2SiSi ., NSi2Si ., or Si3Si .), which have prominent effect on the luminescence intensity, are also studied using electron spin resonance (ESR) measurement. The ESR resu lts suggest that the excess silicon content should not be too high in order to have a strong PL. (C) 1999 Elsevier Science S.A. All rights reserved.