Methods for manufacturing high dielectric constant films
Provided are methods for depositing a cerium doped hafnium containing high-k dielectric film on a substrate. The reagents of specific methods include hafnium tetrachloride, an organometallic complex of cerium and water.
1. A method for forming a high-k dielectric film, comprising:
reacting a mixture of a hafnium-containing precursor and a cerium-containing precursor with a substrate surface in a processing chamber to form a hafnium—and cerium-containing film on the substrate; and
reacting an oxidant with the hafnium—and cerium-containing film on the substrate surface to form a high-k dielectric layer on the substrate surface, the high-k dielectric layer comprising a mixture of hafnium oxide and cerium oxide.
2. The method of claim 1 , wherein the hafnium containing precursor comprises hafnium tetrachloride and optionally further comprises one or more of tetrakis (ethylmethylamido)hafnium, tetrakis(diethylamido)hafnium, tetrakis(dimethylamido)hafnium or combinations thereof.
3. The method of claim 1 , wherein the cerium containing precursor is one or more of a Ce(III) and Ce(IV) organometallic complex.
4. The method of claim 3 , wherein the organometallic complex has a generic formula CeX a Y b Z c , where each of a, b, and c are in the range of 0 and 3 and the sum of a, b and c is about 3 or has a generic formula CeW d X e Y f Z g , where d, e, f and g are each in the range of 0 and 4 and the sum of d, e, f and g is about 4.
5. The method of claim 4 , wherein each of W, X, Y and Z are independently selected from the group consisting of halides, N,N′-diisopropylformamidinate, 2,2-dimethyl-3-methoxypropoxide, bis(trimethylsilyl)amide, 2,2,6,6-tetramethylhepta-3,5-dionate, compounds of the formula
where each of R, R 1 , R 2 , R 3 and R 4 are independently selected from the group consisting of hydrogen and alkyl chains have in the range of 1 to 4 carbons.
6. The method of claim 1 , wherein the oxidant is selected from the group consisting of water, ozone, molecular oxygen and combinations thereof.
7. The method of claim 1 , wherein the high-k dielectric layer comprises at least about 0.5% cerium.
8. The method of claim 1 , further comprising performing one or more of a post-deposition annealing on the high-k dielectric layer and a decoupled plasma nitridation process on the high-k dielectric layer.
9. The method of claim 1 , wherein the film is a layer in a MOSFET exhibiting a leakage current density less than about 100 A/cm 2 at an operating voltage in a range of about −2 volts to about +2 volts.
10. The method of claim 1 , wherein the high-k dielectric has a dielectric constant greater than the dielectric constant of a high-k dielectric film formed without the cerium precursor.
11. The method of claim 1 , wherein the hafnium—and cerium-containing film has a dielectric constant greater than about 30.