Method and systems for forming device structures including high-k dielectric layers and related device structures
Methods for forming a device structure including a high-k dielectric layer are disclosed. An exemplary method includes using a first cyclical deposition process to deposit a dielectric layer on a substrate and using a second cyclical deposition process to deposit a capping layer directly on the dielectric layer. The methods also include thermally annealing the dielectric layer with the capping layer directly thereon to form a high-k dielectric layer. Exemplary device structures are disclosure, such as metal-insulator-metal capacitor structures.
1 . A method of forming a device structure, the method comprising the steps of:
providing a substrate within a reaction chamber;
depositing a hafnium zirconium oxide layer on the substrate by performing one or more deposition super-cycles of a first cyclical deposition process;
depositing a capping layer directly on the hafnium zirconium oxide layer by performing one or more deposition super-cycles of a second cyclical deposition process;
thermally annealing the hafnium zirconium oxide layer with the capping layer directly thereon;
crystallizing at least a portion of the hafnium zirconium oxide layer thereby forming a hafnium zirconium oxide high-k dielectric layer;
selectively removing the capping layer; and
depositing a metallic layer on the hafnium zirconium oxide high-k dielectric layer.
2 . The method of claim 1 , wherein the hafnium zirconium oxide layer comprises a mixed metal oxide, a metal oxide laminate, or mixtures thereof.
3 . The method of claim 2 , wherein depositing the hafnium zirconium oxide layer further comprises depositing a hafnium zirconium oxide layer in an amorphous state with an average layer thickness of greater than zero and less than 4 nanometers (nm).
4 . The method of claim 1 , wherein the capping layer comprises a metal, or a metal oxide, and depositing the capping layer further comprises, depositing at least one of a lutetium oxide, a hafnium oxide, a magnesium oxide, a zirconium oxide, a niobium oxide, an indium oxide, and mixed oxides and metal oxide laminates thereof.
5 . The method of claim 4 , wherein the capping layer comprises a mixed metal oxide or a metal oxide laminate comprising hafnium, lutetium, and oxygen.
6 . The method of claim 5 , wherein depositing the capping layer further comprises depositing a hafnium lutetium oxide capping layer in an amorphous state with an average layer thickness of greater than zero and less than 8 nanometers (nm).
7 . The method of claim 1 , wherein thermally annealing the hafnium zirconium oxide layer further comprises, heating the hafnium zirconium oxide layer to a temperature between 300° C. and 1200° C.
8 . The method of claim 7 , wherein thermally annealing the hafnium zirconium oxide layer does not result in interdiffusion between the hafnium zirconium oxide layer and the capping layer.
9 . The method of claim 7 , wherein thermally annealing the hafnium zirconium oxide layer does not result in additional strain/stress in the hafnium zirconium oxide high-k dielectric layer.
10 . The method of claim 1 , wherein crystallizing at least a portion of the hafnium zirconium oxide layer further comprises, crystallizing at least a portion of the capping layer.
11 . The method of claim 10 , wherein the hafnium zirconium oxide high-k dielectric layer has a dielectric constant great than 30 with an average layer thickness of less than 4 nanometers (nm).
12 . The method of claim 1 , wherein selectively removing the capping layer further comprises, selectively etching the capping layer employing a hydrofluoric acid based etchant, an ammonia based etchant, or a hydrochloric acid and hydrogen peroxide based etchant.