Correlation of charge transport to intrinsic strain in silicon oxynitride and Si-rich silicon nitride thin films

摘要

Poole-Frenkel emission in Si-rich nitride and silicon oxynitride thin films is studied in conjunction with compositional aspects of their elastic properties. For Si-rich nitrides varying in composition from SiN_(1.33) to SiN_(0.54), the Poole-Frenkel trap depth (φ_(B)) decreases from 1.08 to 0.52 eV as the intrinsic film strain (∈_(i)) decreases from 0.0036 to -0.0016. For oxynitrides varying in composition from SiN_(1.33) to SiO_(1.49)N_(0.35), φ_(B) increases from 1.08 to 1.53 eV as ∈_(i) decreases from 0.0036 to 0.0006. In both material systems, a direct correlation is observed between φ_(B) and ∈_(i). Compositionally induced strain relief as a mechanism for regulating φ_(B) is discussed.