Processing dependence of metal/tunnel-oxide/silicon junctions

Abstract
The effects of process variations on the fixed-charge density, interface-state density, and tunneling properties of tunnel oxides on (100) silicon are discussed. Annealing the oxide in nitrogen reduces the fixed-charge and interface-state densities substantially, but also causes a marked increase in oxide capacitance. Anneals in forming gas before metallization alter the interface-state distribution and decrease the insulating qualities of the tunneling oxides. Postmetallization anneals in forming gas reduce the interface-state density to 1×1011 cm−2 eV−1 or below, and appear not to affect the current through the oxide. No evidence for metal-induced interface states is observed.