Methods of fabricating metal-insulator-metal capacitors with a chemical barrier layer in a lower electrode
A metal-insulator-metal (MIM) capacitor includes a lower electrode, a dielectric layer, and an upper electrode. The lower electrode includes a first conductive layer, a chemical barrier layer on the first conductive layer, and a second conductive layer on the chemical barrier layer. The chemical barrier layer is between the first and second conductive layers and is a different material than the first and second conductive layers. The dielectric layer is on the lower electrode. The upper electrode is on the dielectric layer opposite to the lower electrode. The first and second conductive layers can have the same thickness. The chemical barrier layer can be thinner than each of the first and second conductive layers. Related methods are discussed.
1. A method of fabricating a metal-insulator-metal (MIM) capacitor, the method comprising:
forming a first conductive layer on a semiconductor substrate and with major portions extending upward away from the semiconductor substrate;
forming a chemical barrier layer on the first conductive layer including on the major portions extending away from the semiconductor substrate;
forming a second conductive layer on the chemical barrier layer and with major portions extending upward away from the semiconductor substrate, wherein the chemical barrier layer is between the first and second conductive layers, and the chemical barrier layer comprises a different material than the first and second conductive layers, and wherein the first conductive layer, the chemical barrier layer, and the second conductive layer provide a lower electrode;
forming a dielectric layer on the lower electrode; and
forming an upper electrode on the dielectric layer,
wherein forming a first conductive layer and forming a second conductive layer each comprise depositing a layer of titanium nitride (TiN), tantalum nitride (TaN), tungsten nitride (WN), ruthenium (Ru), platinum (Pt), ruthenium oxide (RuO 2 ), and/or platinum oxide (PtO 2 ).
2. The method according to claim 1 , wherein forming a first conductive layer and forming a second conductive layer each comprise a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, and/or a sequential flow deposition (SFD) process.
3. The method according to claim 1 , wherein the chemical barrier layer is formed from polysilicon (poly-Si), polysilicon germanium (poly-SiGe), titanium (Ti), hafnium oxide (HfO 2 ), hafnium oxynitride (HfON), titanium oxide (TiO 2 ), and/or titanium oxynitride (TiON).
4. The method according to claim 3 , wherein forming a chemical barrier layer comprises a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, and/or a rapid thermal oxidation process.
5. A method of fabricating a metal-insulator-metal (MIM) capacitor the method comprising:
forming an interlayer insulating layer on a semiconductor substrate;
forming a conductive plug that extends from a surface of the semiconductor substrate through the interlayer insulating layer;
forming an etch stopper on the interlayer insulating layer;
forming a mold oxide layer on the etch stopper;
partially etching the mold oxide layer and the etch stopper to form an opening that exposes the conductive plug and define a lower electrode region;
forming a first conductive layer on sidewalls of the opening of the mold oxide and the conductive plug in the lower electrode region;
forming a chemical barrier layer on the first conductive layer;
forming a second conductive layer on the chemical barrier layer, wherein the chemical barrier layer is between the first and second conductive layers, and the chemical barrier layer comprises a different material than the first and second conductive layers;
planarizing the first conductive layer, the chemical barrier layer, and the second conductive layer to expose an upper surface of the mold oxide layer, wherein the planarized first conductive layer, chemical barrier layer, and second conductive layer form a lower electrode;
removing the mold oxide layer to expose the lower electrode and the etch stopper;
forming a dielectric layer on the lower electrode and the etch stopper; and
forming an upper electrode on the dielectric layer,
wherein forming a first conductive layer and forming a second conductive layer each comprise depositing a layer of titanium nitride (TiN), tantalum nitride (TaN), tungsten nitride (WN), ruthenium (Ru), platinum (Pt), ruthenium oxide (RuO 2 ), and/or platinum oxide (PtO 2 ).
6. The method according to claim 5 , wherein:
forming an interlayer insulating layer comprises depositing an insulating layer on the semiconductor substrate; and
forming a conductive plug comprises:
etching a portion of the insulating layer to expose a portion of the semiconductor substrate and form a contact hole thereto; and
filling the contact hole with a metal to form the conductive plug.
7. The method according to claim 5 , wherein:
forming an interlayer insulating layer comprises depositing an insulating layer on the semiconductor substrate; and
forming a conductive plug comprises:
etching a portion of the insulating layer to expose a portion of the semiconductor substrate and form a contact hole thereto; and
filling the contact hole with doped polysilicon to form the conductive plug.
8. The method according to claim 7 , after partially etching the mold oxide layer and the etch stopper to expose the conductive plug and define a lower electrode region and before forming a first conductive layer on the mold oxide and the conductive plug in the lower electrode region, the method further comprising forming an ohmic contact layer on an exposed surface of the conductive plug.
9. The method according to claim 8 , further comprising:
forming a transition metal layer on the exposed surface of the conductive plug and the mold oxide layer; and
annealing the transition metal layer to form a transition metal silicide layer on a surface of the conductive plug.
10. The method according to claim 9 , after annealing the transition metal layer to form a transition metal silicide layer on a surface of the conductive plug, the method further comprising carrying out a nitridation process on the transition metal layer.
11. The method according to claim 9 , after annealing the transition metal layer to form a transition metal silicide layer on a surface of the conductive plug, the method further comprising removing the transition metal layer.
12. The method according to claim 5 , wherein forming a first conductive layer and forming a second conductive layer each comprise a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, and/or a sequential flow deposition (SFD) process.
13. The method according to claim 5 , wherein the chemical barrier layer is formed from polysilicon (poly-Si), polysilicon germanium (poly-SiGe), titanium (Ti), hafnium oxide (HfO 2 ), hafnium oxynitride (HfON), titanium oxide (TiO 2 ), and/or titanium oxynitride (TiON).
14. The method according to claim 13 , wherein forming a chemical barrier layer comprises a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, and/or a rapid thermal oxidation process.
15. The method according to claim 5 , after forming a second conductive layer on the chemical barrier layer and before planarizing the first conductive layer, the chemical barrier layer, and the second conductive layer to expose an upper surface of the mold oxide layer, the method further comprising forming a sacrificial layer on the second conductive layer.
16. The method according to claim 15 , wherein planarizing the first conductive layer, the chemical barrier layer, and the second conductive layer to expose an upper surface of the mold oxide layer comprises chemical mechanical polishing and/or an etching the sacrificial layer, the first conductive layer, the chemical barrier layer, and the second conductive layer to expose an upper surface of the mold oxide layer.
17. The method according to claim 5 , wherein the mold oxide layer is removed using an LAL solution of deionized water, NH 4 F and HF and/or a HF solution.
18. The method according to claim 5 , wherein the dielectric layer is formed from hafnium oxide, zirconium oxide, lanthanum oxide, and/or tantalum oxide.
19. The method according to claim 5 , wherein the upper electrode is formed from the same material as the first conductive layer and/or the second conductive layer.