Barrier layer model determined by XPS data for tunneling current reductions at monolayer nitrided Si–SiO 2 interfaces

Abstract

This paper builds on previous work that has demonstrated that interfacial suboxide transition regions at Si–SiO 2 interfaces modify tunneling oscillations in the Fowler–Nordheim regime. This paper extends this approach to the direct tunneling regime, emphasizing differences in interfacial transition regions between Si–SiO 2 interfaces with and without monolayer level interface nitridation. Tunneling currents in devices with the same oxide-equivalent thickness are reduced by monolayer level interfacial nitrogen with respect to devices without interface nitridation for both substrate and gate injection in both the direct and Fowler–Nordheim tunneling regimes. These decreases have been combined with physically thicker stacked oxide/nitride dielectrics to yield significantly reduced tunneling compared to devices with oxides of the same equivalent oxide thickness, t ox-eq; e.g., tunneling currents ∼5×10 −3 A/cm 2 at 1 V for t ox-eq∼1.6 nm have been obtained.