Role of oxygen on the dangling bond configuration of low oxygen content SiNx :H films deposited at room temperature

Abstract

SiNx:H films with a wide composition range and, some of them, with low oxygen content are deposited at room temperature. The defects observed in the films are attributed to Si-dangling bonds, with a structure depending on film composition. For the N-rich films they are of the form . Si=(N-3), whereas for the films with similar [N]/[Si] ratio but containing oxygen, the predominant defect is proposed to be Si=(Si2O), despite of the high N content and the low O content of these films. The spin density of the films has been related to the bonds that hydrogen establishes (either Si-H or N-H), with the maximum value corresponding to the minimum hydrogen content. Both maximum and minimum values, respectively, are obtained at the silicon percolation limit of the Si-Si bonds into the SiNx:H network, x similar to 1.10.