Bonding configuration and defects in amorphous SiNx:H films

Amorphous SiNx:H films were prepared by rf glow discharge of SiH4-NH3 mixtures at 300 °C, and the optical properties and the density Ns of Si dangling bonds obtained from electron spin resonance were investigated as a function of the N content x. The slope E0 in the Urbach form of the absorption coefficient and Ns, respectively, have a maximum at x=1.2 and 0.7. The dependence of E0 on x was examined on the basis of the random-bonding model including H atoms, and the dependence of Ns was connected with the optical gap and E0, according to the weak-bond dangling-bond conversion model.