Methods for depositing nickel films and for making nickel silicide and nickel germanide
In one aspect, methods of silicidation and germanidation are provided. In some embodiments, methods for forming metal silicide can include forming a non-oxide interface, such as germanium or solid antimony, over exposed silicon regions of a substrate. Metal oxide is formed over the interface layer. Annealing and reducing causes metal from the metal oxide to react with the underlying silicon and form metal silicide. Additionally, metal germanide can be formed by reduction of metal oxide over germanium, whether or not any underlying silicon is also silicided. In other embodiments, nickel is deposited directly and an interface layer is not used. In another aspect, methods of depositing nickel thin films by vapor phase deposition processes are provided. In some embodiments, nickel thin films are deposited by ALD. Nickel thin films can be used directly in silicidation and germanidation processes.
1. A method of depositing a conformal nickel thin film on a substrate by multiple cycles of a vapor deposition process, each cycle comprising alternately and sequentially contacting a substrate in a reaction space with a vapor phase nickel precursor, a second precursor and a third precursor to form a conformal elemental nickel thin film, wherein the second precursor is an organic reducing agent comprising at least one functional group selected from the group consisting of alcohol (—OH), aldehyde (—CHO), or carboxylic acid (—COOH), and wherein the third precursor is selected from hydrogen and forming gas.
2. The method of claim 1 , wherein no more than about one monolayer of the nickel precursor is formed on the substrate surface in each cycle.
3. The method of claim 1 , wherein the nickel precursor is selected from the group consisting of nickel betadiketonate compounds, nickel betadiketiminato compounds, nickel aminoalkoxide compounds, nickel amidinate compounds, nickel cyclopentadienyl compounds, nickel carbonyl compounds and combinations thereof.
4. An atomic layer deposition-type process for forming a conformal elemental Ni thin film on a substrate in a reaction chamber comprising multiple Ni deposition cycles, each deposition cycle comprising:
providing a first vapor phase reactant pulse comprising a first Ni precursor into the reaction chamber to form a layer of the Ni precursor on the substrate;
removing excess first reactant from the reaction chamber;
providing a second vapor phase reactant pulse to the reaction chamber such that the second reactant reacts with the first Ni precursor on the substrate in a self-limiting manner to form elemental Ni;
removing excess second reactant and reaction byproducts, if any, from the reaction chamber; and
contacting the substrate with a third reactant,
wherein the second vapor phase reactant is an organic reducing agent comprising at least one functional group selected from the group consisting of alcohol (—OH), aldehyde (—CHO), or carboxylic acid (—COOH), and wherein the third reactant is selected from hydrogen and forming gas.
5. The method of claim 4 , wherein the first Ni precursor is selected from the group consisting of nickel betadiketonate compounds, nickel betadiketiminato compounds, nickel aminoalkoxide compounds, nickel amidinate compounds, nickel cyclopentadienyl compounds, nickel carbonyl compounds and combinations thereof.
6. The method of claim 4 , wherein the first nickel precursor is bis(4-N-ethylamino-3-penten-2-N-ethyliminato)nickel (II).
7. An ALD-type process for depositing conformal Ni thin films on a substrate in a reaction space comprising multiple Ni deposition cycles, each deposition cycle comprising:
providing a first vapor phase reactant pulse comprising a first Ni precursor into the reaction space to form a layer of the Ni precursor on the substrate;
removing excess first reactant from the reaction space;
providing a second vapor phase reactant pulse to the reaction space, wherein the second reactant is an organic reducing agent;
removing excess second reactant and reaction byproducts, if any, from the reaction space; and
providing a third vapor phase reactant pulse to the reaction space, wherein the third reactant is hydrogen or forming gas; and
removing excess third reactant and reaction byproducts, if any, from the reaction space,
wherein the deposition cycle forms elemental nickel and the process forms a conformal Ni thin film.
8. The method of claim 7 , wherein the first Ni precursor is selected from the group consisting of nickel betadiketonate compounds, nickel betadiketiminato compounds, nickel aminoalkoxide compounds, nickel amidinate compounds, nickel cyclopentadienyl compounds, nickel carbonyl compounds and combinations thereof.
9. The method of claim 8 , wherein the first Ni precursor has the formula X(acac) y or X(thd) y , where X is a metal, y is from about 2 to about 3 and thd is 2,2,6,6-tetramethyl-3,5-heptanedionato.
10. The method of claim 7 wherein the first nickel precursor is bis(4-N-ethylamino-3-penten-2-N-ethyliminato)nickel (II).
11. The method of claim 7 , wherein the organic reducing agent is provided after the Ni precursor but before the hydrogen or forming gas.
12. The method of claim 7 , wherein the organic reducing agent is provide after the Ni precursor and after the hydrogen or forming gas.
13. The method of claim 1 , wherein the conformal nickel thin film has a thickness non-uniformity between 5% and 40%.
14. The process of claim 4 , wherein the conformal elemental Ni thin film has a thickness non-uniformity between 5% and 40%.
15. The process of claim 7 , wherein the conformal Ni thin films have a thickness non-uniformity between 5% and 40%.