Yttrium and titanium high-k dielectric films
First Claim
1. A semiconductor layer stack comprising:
- a first conductive layer;
a second conductive layer; and
a dielectric disposed between the first conductive layer and the second conductive layer,the dielectric comprising a Ti—
Y—
Ox layer having a yttrium-to-total-metal (Y/(Y+Ti)) constituency of between approximately sixteen to forty-one percent yttrium,the dielectric having a thickness between 5 nanometers and 20 nanometers,the dielectric being formed by a physical vapor deposition (PVD) process, the PVD process comprising reactive co-sputtering of a first source and a second source,wherein the first source comprises metallic yttrium, andwherein the second source comprises metallic titanium,wherein yttrium and titanium are intermixed in the dielectric such that the dielectric is a monolayer having a homogeneous composition;
wherein the dielectric is formed in an oxygen-rich environment.
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Abstract
This disclosure provides (a) methods of making an oxide layer (e.g., a dielectric layer) based on yttrium and titanium, to have a high dielectric constant and low leakage characteristic and (b) related devices and structures. An oxide layer having both yttrium and titanium may be fabricated either as an amorphous oxide or as an alternating series of monolayers. In several embodiments, the oxide is characterized by a yttrium contribution to total metal that is specifically controlled. The oxide layer can be produced as the result of a reactive process, if desired, via either a PVD process or, alternatively, via an atomic layer deposition process that employs specific precursor materials to allow for a common process temperature window for both titanium and yttrium reactions.
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Citations
13 Claims
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1. A semiconductor layer stack comprising:
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a first conductive layer; a second conductive layer; and a dielectric disposed between the first conductive layer and the second conductive layer, the dielectric comprising a Ti—
Y—
Ox layer having a yttrium-to-total-metal (Y/(Y+Ti)) constituency of between approximately sixteen to forty-one percent yttrium,the dielectric having a thickness between 5 nanometers and 20 nanometers, the dielectric being formed by a physical vapor deposition (PVD) process, the PVD process comprising reactive co-sputtering of a first source and a second source, wherein the first source comprises metallic yttrium, and wherein the second source comprises metallic titanium, wherein yttrium and titanium are intermixed in the dielectric such that the dielectric is a monolayer having a homogeneous composition;
wherein the dielectric is formed in an oxygen-rich environment. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A semiconductor layer stack comprising:
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a first conductive layer; a second conductive layer; and an amorphous oxide layer disposed between the first conductive layer and the second conductive layer, the amorphous oxide layer comprising yttrium and titanium, the amorphous oxide layer having a thickness between 5 nanometers and 20 nanometers, wherein yttrium and titanium are intermixed in the amorphous oxide layer such that the dielectric is a monolayer having a homogeneous composition, wherein the amorphous oxide layer is characterized by a structure having substantially no crystalline yttrium oxide and substantially no crystalline titanium oxide, wherein the amorphous oxide layer has a dielectric constant equal to or greater than fifty-five, wherein the amorphous oxide layer has a yttrium-to-total-metal (Y/(Y+Ti)) constituency of between approximately sixteen to forty-one percent yttrium, and wherein the amorphous oxide layer is formed by a physical vapor deposition (PVD) process, the PVD process comprising reactive co-sputtering of a first source and a second source, wherein the first source comprises metallic yttrium, and wherein the second source comprises metallic titanium;
wherein the amorphous oxide layer is formed in an oxygen-rich environment. - View Dependent Claims (12, 13)
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Specification