Separate and independent reductions in direct tunneling in oxide/nitride stacks with monolayer interface nitridation associated with the (i) interface nitridation and (ii) increased physical thickness

Direct tunneling limits aggressive scaling of thermally grown oxides to about 1.6 nm, a thickness at which the tunneling current density J(g) at 1 V is similar to 1 A/cm(2), This article demonstrates that stacked gate dielectrics prepared by remote plasma processing and including (i) ultrathin nitrided SiO(2) interfacial layers and (ii) either silicon nitride or oxynitride bulk dielectrics can extend the equivalent oxide thickness to 1.1-1.0 nm before J(g) exceeds 1 A/cm(2). Significant reductions in direct tunneling are derived from (i) interface nitridation at the monolayer level and (ii) the increased physical thickness of the nitride or oxynitride alloy layers. The "portability" of the interface contribution is demonstrated by combining the nitrided SiO(2) interface layers with transition-metal oxides, e.g., Ta(2)O(5), in stacked gate dielectric structures and obtaining essentially the same reductions in tunneling current on n- and p-type substrates with respect to non-nitrided plasma-grown interface layers. (C) 2000 American Vacuum Society. [S0734-2101(00)18304-6].