Polymer-assisted deposition of films
A polymer assisted deposition process for deposition of metal nitride films and the like is presented. The process includes solutions of one or more metal precursor and soluble polymers having binding properties for the one or more metal precursor. After a coating operation, the resultant coating is heated at high temperatures under a suitable atmosphere to yield metal nitride films and the like. Such films can be conformal on a variety of substrates including non-planar substrates. In some instances, the films can be epitaxial in structure and can be of optical quality. The process can be organic solvent-free.
1. A process of preparing a uniform metal nitride film comprising:
preparing a homogeneous solution of metal-bound polymer by combining a soluble metal precursor and a soluble polymer selected from the group consisting of polyethyleneimine, derivatives of polyethyleneimine, polyacrylic acid, and poly(ethylene-maleic acid) in a suitable solvent,
applying the homogeneous solution onto a substrate to form a polymer and metal containing layer thereon,
heating said substrate in a reducing atmosphere at temperatures and for time characterized as sufficient to remove said polymer from said polymer and metal containing layer and form a uniform metal nitride film.
2. The process of claim 1 wherein said heating said substrate includes first heating said substrate in a hydrogen-containing atmosphere at temperatures and for time characterized as sufficient to remove said polymer from said polymer and metal containing layer and second further heating said substrate in an ammonia atmosphere at temperatures and for time characterized as sufficient to form a conformal metal nitride film.
3. The process of claim 2 wherein said reducing atmosphere is a mixture of hydrogen and nitrogen.
4. The process of claim 3 wherein said reducing atmosphere is a mixture of about 6 percent hydrogen and about 94 percent nitrogen by volume.
5. The process of claim 1 wherein said metal is titanium, aluminum or gallium.
6. The process of claim 1 wherein said metal is a titanium and aluminum mixture.
7. The process of claim 1 wherein said metal is molybdenum, niobium, titanium, aluminum or gallium.