SEMICONDUCTOR DEVICE, METHOD OF MANUFACTURING THE SAME AND ADSORPTION SITE BLOCKING ATOMIC LAYER DEPOSITION METHOD

• US 20120077322A1
• Filed: 09/26/2011
• Published: 03/29/2012
• Est. Priority Date: 09/27/2010
• Status: Active Grant

• Current Assignee: Elpida Memory Incorporated (Micron Technology, Inc.), Tokyo Electron Limited
• Original Assignee: Elpida Memory Incorporated (Micron Technology, Inc.), Tokyo Electron Limited
• Inventors: HIROTA, Toshiyuki, KIYOMURA, Takakazu, MOROZUMI, Yuichiro, HISHIYA, Shingo
• Granted Patent: US 8,288,241 B2
• Time in Patent Office: Days
• US Class Current: 438/381
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02186 the material containing titanium, e.g. TiO2
• CPC Class Codes: H01L 21/02189 the material containing zirconium, e.g. ZrO2
• CPC Class Codes: H01L 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 28/40 Capacitors

Abstract

To provide a dielectric film having good crystallinity while suppressing an influence of the size effects and preventing the dielectric film from being divided by an Al-doped layer although there is provided the Al-doped layer for improving the leakage characteristics in the dielectric film of a capacitor, the dielectric film has at least one Al-doped layer, and an area density of Al atoms in one layer of the Al-doped layer is smaller than 1.4E+14′ atoms/cm². Further, to achieve the area density, there is employed a combination of formation of a dielectric film using a general ALD method and Al doping using an adsorption site blocking ALD method including adsorbing a blocker molecule restricting an adsorption site of an Al source, adsorbing the Al source, and introducing a reaction gas for reaction.

Claims

1. An adsorption site blocking atomic layer deposition method of depositing, on a base material, a first material different from the base material by an atomic layer deposition method,

before introducing a first source gas including a first precursor as a source of the first material in a film forming space, introducing a second source gas including a blocker molecule having a group with a low affinity to the first precursor in the film forming space, and restricting an adsorption site of the first precursor on the base material by adsorbing the blocker molecule on the base material,

purging the second source gas,

introducing the first source gas in the film forming space, and adsorbing the first precursor on the adsorption site restricted on the base material,

purging the first source gas, and

introducing a reaction gas in the film forming space, and reacting the reaction gas with at least the first precursor to be converted into the first material.

2. The method according to claim 1, wherein the blocker molecule includes a group which is easy to be adsorbed on the base material, and a group which is relatively difficult to be adsorbed on the base material, the blocker molecule itself performs an oriented adsorption such that the group which is difficult to be adsorbed is self-organized toward an outside, and the group which is difficult to be adsorbed is a group having a low affinity to the first precursor to block adsorption of the first precursor to the blocker molecule.

3. The method according to claim 2, wherein the base material is metal oxide,

the blocker molecule is a metal complex which has a metal atom constituting the metal oxide of the base material and has the group which is easy to be adsorbed on the base material and the group which is relatively difficult to be adsorbed on the base material as a substituent or ligand, and

the reaction gas is an oxidative gas, and the reaction gas reacts with the blocker molecule to form a film in which the first material is doped in the metal oxide of the base material.

4. The method according to claim 1, wherein the blocker molecule is a monocyclopentadienyl metal complex coordinating a cyclopentadiene ring, which may have a substituent, and having a plurality of polar groups.

5. The method according to claim 4, wherein the monocyclopentadienyl metal complex is cyclopentadienyl tris(dimethylamino)zirconium, methylcyclopentadienyl tris(dimethylamino)zirconium or methylcyclopentadienyl tris(dimethylamino)titanium.

6. A method of manufacturing a semiconductor device including a capacitor having a dielectric film between a lower electrode and an upper electrode, the method comprising:

forming the dielectric film on the lower electrode by an atomic layer deposition method; and

forming the upper electrode on the dielectric film,

wherein the dielectric film includes first and second dielectric films formed of the same material, and an Al-doped layer inserted between the first and second dielectric films, and

forming the Al-doped layer comprises sequentially;

(1) introducing a second source gas including a blocker molecule having a group with a low affinity to an Al precursor, and adsorbing the blocker molecule on the first dielectric film,

(2) purging the second source gas,

(3) adsorbing a first source gas including the Al precursor on an adsorption site of the first dielectric film on which the blocker molecule is not adsorbed,

(4) purging the first source gas,

(5) oxidizing Al atom in at least the Al precursor by supplying a reaction gas to react with the blocker molecule adsorbed on the first dielectric film and the Al precursor, and

(6) purging an unreacted portion of the reaction gas and a by-product.

7. The method according to claim 6, wherein the blocker molecule includes a group which is easy to be adsorbed on the first dielectric film, and a group which is relatively difficult to be adsorbed on the first dielectric film, the blocker molecule itself performs an oriented adsorption such that the group which is difficult to be adsorbed is self-organized toward an outside, and the group which is difficult to be adsorbed is a group having a low affinity to the Al precursor to block adsorption of the Al precursor to the blocker molecule.

8. The method according to claim 6, wherein the blocker molecule is a metal complex which has metal atom M constituting the first dielectric film and has a group which is easy to be adsorbed and a group which is relatively difficult to be adsorbed as a substituent or ligand, and

the reaction gas reacts with the blocker molecule to form metal oxide constituting the first dielectric film.

9. The method according to claim 6, wherein the blocker molecule is a monocyclopentadienyl metal complex having metal atom M constituting the first dielectric film, polar groups and a cyclopentadiene ring which may have a substituent, and the reaction gas reacts with the blocker molecule to form metal oxide constituting the first dielectric film.

10. The method according to claim 6, wherein the Al precursor is trimethylaluminum.

11. The method according to claim 10, wherein the first and second dielectric films are formed of an zirconium oxide film, and the blocker molecule is cyclopentadienyl tris(dimethylamino)zirconium or methylcyclopentadienyl tris(dimethylamino)zirconium.

12. The method according to claim 11, wherein the first and second dielectric films are formed by an atomic layer deposition method using the blocker molecule as a precursor.

13. The method according to claim 12, wherein the upper and lower electrodes of the capacitor are formed of a TiN film, and further comprising forming a titanium oxide film at an interface between the TiN film and the zirconium oxide film.

14. The method according to claim 10, wherein the first and second dielectric films are formed of a titanium oxide film, and the blocker molecule is methylcyclopentadienyl tris(dimethylamino)titanium.

15. The method according to claim 14, wherein the first and second dielectric films are formed by an atomic layer deposition method using the blocker molecule as a precursor.

16. The method according to claim 14, wherein the lower electrode of the capacitor is formed of RuO₂.

17. The method according to claim 6, wherein the Al-doped layer is formed as at least one layer in the dielectric film, and film formation of one layer is carried out by performing only one cycle of the steps (1) to (6).

18. The method according to claim 17, wherein an area density of Al atoms in one layer of the Al-doped layer is smaller than 1.4E+14 atoms/cm².

19. The method according to claim 18, wherein the area density of Al atoms in one layer of the Al-doped layer is equal to or smaller than 1.0E+14 atoms/cm².

20. The method according to claim 17, wherein a concentration of Al atoms included in the dielectric film ranges from 0.2 to 2 atom % as a ratio of the number of atoms represented by Al/(Al+M) with respect to metal atom M constituting the dielectric film.