| AVS 60th International Symposium and Exhibition | |
| Electronic Materials and Processing | Thursday Sessions |
| Session EM-ThA |
| Session: | Materials and Process for Advanced Interconnects II |
| Presenter: | M. Mutch, Penn State University |
| Authors: | M. Mutch, Penn State University P.M. Lenahan, Penn State University S.W. King, Intel Corporation |
| Correspondent: | Click to Email |
SiCN:H films have great promise as etch stop layers in interlayer dielectric structures [1]. Unfortunately, very little is known about the physical mechanisms of electronic transport in these materials. In this study we have utilized variable field electrically detected magnetic resonance (EDMR) almost certainly via spin-dependent trap-assisted tunneling (SDT) in variable range hopping [2]. Our results of are of significance for several reasons. First, they demonstrate that SDT/EDMR is sensitive enough to detect defects involved in transport within these films. The simple observation of an EDMR spectrum undoubtedly links the defects responsible for the spectrum to electronic transport. Secondly, they provide information about the physical and chemical nature of the defects involved of transport within the films.
The films studied were deposited via PECVD and have a composition of 45% Si, 29% C, 23% N and 3% O. The SDT/EDMR measurements were taken on a home-built X-band (≈9.5 GHz) EDMR spectrometer at room temperature utilizing specially thinned SiCN:H films deposited on p-type silicon with titanium electrode. We observe quite strong SDT/EDMR traces with a zero crossing of g = 2.003 and a peak-to-peak line width of 14 Gauss. (The g is determined by the expression g = hν/(µBB ) , where h is Planck’s constant, ν is microwave frequency, µBis the Bohr magneton and B is the magnetic field at resonance. We find that the SDT/EDMR response is quite strongly voltage dependent and find a fractional contribution of the SDT/EDMR response to be highly asymmetric, with a much larger ΔI/I corresponding to negative gate polarity. It is clear that the paramagnetic sites observed to not involve electron wave function primarily localized on either hydrogen or nitrogen as both of these nuclei have virtually 100% abundant isotopes with nuclear moments [3]. The zero crossing of g = 2.003 and a 14 G line width are essentially a perfect match with the well characterized EPR spectrum of K-centers, silicons back-bonded to three hydrogens. The K-centers have been studied extensively in silicon nitride [4, 5]. We thus tentatively assign the observed EDMR to K-centers and also tentatively conclude that the K-centers are important defects in transport in SiCN:H films under study.
[1] J. Martin et. al, IEEE Proceedings, vol ., no., pp. 42, 44 (2002).
[2] J.T. Ryan et. al, J. Appl. Phys., vol 108, 064511 (2010).
[3] J. Weil et. al, Electron Paramagnetic Resonance. Wiley-Interscience (1994).
[4] D.T. Krick et. al, J. Appl. Phys. 64, 3558 (1988)
[5] P. M. Lenahan et. al, Appl. Surf. Sci. 39, 392 (1989).