There is a continuing interest to incorporate oxide dielectrics into semiconductor constructions. Among the dielectrics that are of particular interest are those represented by the formula MOz, where M represents a metal, O is oxygen, and z is a number greater than 0, and typically less than or equal to 8. The metal can be a transition metal, such as, for example, hafnium, or a non-transition metal, such as, for example, aluminum. The dielectric materials can be useful in, for example, capacitor constructions.
A difficulty in utilizing metal oxide dielectrics (MOz) is that diffusion can occur between the dielectric materials and structures proximate to the dielectric materials, and such diffusion can adversely affect properties of the dielectric material and/or the structures proximate to the dielectric material. For instance, if a conductive structure comprises conductively-doped silicon and MOz is formed directly on the conductively-doped silicon, oxygen from the MOz can interact with the silicon to oxidize the silicon. The oxidized silicon will no longer have the desired conductive properties of conductively-doped silicon.
The problems discussed above can be alleviated, and even prevented, through utilization of a metal nitride barrier layer. The metal nitride can be represented as MNy, where M is metal, N is nitrogen, and y is a number greater than 0 and typically less than 8. The metal nitride is frequently referred to as a diffusion barrier layer, as the metal nitride alleviates, and frequently even prevents, diffusion to and/or from a metal oxide dielectric. U.S. Pat. No. 5,741,721 describes exemplary structures in which metal oxide dielectric materials are formed over metal nitride barrier layers. U.S. Pat. No. 5,741,721 specifically describes processes in which a metal nitride layer is formed over a semiconductor substrate, and subsequently a surface of the metal nitride layer is oxidized to form a metal oxide dielectric material.
The processing described in U.S. Pat. No. 5,741,721 can be difficult to incorporate into various semiconductor fabrication processes. Accordingly, it would be desirable to develop alternative methods for forming metal oxide dielectric material adjacent diffusion barrier layers.