Metal-insulator-metal stack and method for manufacturing the same
A method for manufacturing a metal-insulator-metal (MIM) stack is described. The method includes forming a temporary stack by depositing a bottom electrode comprising at least one metal layer; depositing a dielectric comprising at least one layer of a dielectric material having a first dielectric constant value; and depositing a top electrode comprising at least one metal layer. The step of depositing the bottom and/or top electrode includes depositing a non-conductive metal oxide layer directly in contact with the dielectric; and after the step of depositing the bottom and/or top electrode's non-conductive metal oxide layer and the dielectric, subjecting the temporary stack to a stimulus, which transforms the non-conductive metal oxide into a thermodynamically stable oxide having conductive properties or into a metal, and the dielectric material into a crystalline form having a second dielectric constant value higher than the first dielectric constant value, thereby creating the final MIM stack.
1. A method for manufacturing a metal-insulator-metal (MIM) stack, comprising:
forming a temporary stack by:
depositing a bottom electrode comprising at least one metal layer;
depositing a dielectric comprising at least one layer of a dielectric material having a first dielectric constant value; and
depositing a top electrode comprising at least one metal layer;
wherein depositing at least one of the bottom electrode or the top electrode includes depositing a non-conductive metal oxide layer directly in contact with the dielectric, wherein the non-conductive metal oxide is in a metastable and high oxidation state; and
after depositing the non-conductive metal oxide layer and the dielectric, subjecting the temporary stack to a stimulus to cause the non-conductive metal oxide layer to release oxygen and transform into a thermodynamically stable oxide having conductive properties or into a metal, and to cause the dielectric to incorporate the released oxygen and transform into a crystalline form having a second dielectric constant value higher than the first dielectric constant value.
2. The method according to claim 1 , wherein the at least one metal layer of the bottom or top electrodes prevents diffusion of the released oxygen from the non-conductive metal oxide layer into the metal layer.
3. The method according to claim 1 , wherein the at least one metal layer is a nitride of tantalum (Ta), tungsten (W), carbon (C), aluminum (Al), titanium (Ti), or a combination thereof, and wherein the non-conductive metal oxide layer includes one or more of molybdenum (Mo), ruthenium (Ru), tungsten (W), or vanadium (V).
4. The method according to claim 3 , wherein the non-conductive metal oxide layer is includes one or more of molybdenum trioxide (MoO 3 ), ruthenium dioxide (RuO 2 ), tungsten trioxide (WO 3 ), or vanadium pentoxide (V 2 O 5 ).
5. The method according to claim 1 , wherein a thickness of the non-conductive metal oxide layer is equal to or less than 2 nm, and wherein a thickness of the at least one metal layer is equal to or greater than 5 nm.
6. The method according to claim 1 , wherein the stimulus is one or more of a thermal, pressure, or radiation stimulus in a neutral or reducing environment.
7. The method according to claim 1 , further comprising subjecting the temporary stack to a stimulus to cause the non-conductive metal oxide layer to release oxygen and transform into a thermodynamically stable oxide having conductive properties or into a metal, and concomitantly to cause the dielectric to directly incorporate the released oxygen and transform into a crystalline form having a second dielectric constant value higher than the first dielectric constant value.