Methods of using atomic layer deposition to deposit a high dielectric constant material on a substrate

• US 6,420,279 B1
• Filed: 06/28/2001
• Issued: 07/16/2002
• Est. Priority Date: 06/28/2001
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ono, Yoshi, Zhuang, Wei-Wei, Solanki, Rajendra
• Primary Examiner(s): Ghyka, Alexander G.
• Application Number:
  US09/894,941
• Time in Patent Office: 383 Days
• Field of Search: 438/785, 438/685, 438/758
• US Class Current: 438/785
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/45529 specially adapted for making a layer stack of alternating different compositions or gradient compositions
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• CPC Class Codes: H01L 21/02189 the material containing zirconium, e.g. ZrO2
• CPC Class Codes: H01L 21/02192 the material containing at least one rare earth metal element, e.g. oxides of lanthanides, scandium or yttrium
• CPC Class Codes: H01L 21/02194 the material containing more than one metal element
• 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 21/02205 the layer being characterised by the precursor material for deposition
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/31604 Deposition from a gas or vapour H01L21/31691, H01L21/31695 take precedence

Abstract

Methods of forming hafnium oxide, zirconium oxide and nanolaminates of hafnium oxide and zirconium oxide are provided. These methods utilize atomic layer deposition techniques incorporating nitrate-based precursors, such as hafnium nitrate and zirconium nitrate. The use of these nitrate based precursors is well suited to forming high dielectric constant materials on hydrogen passivated silicon surfaces.

Claims

1. A method of forming a high-k dielectric film on a substrate comprising the steps of:

a) providing a hydrogen passivated silicon surface on the semiconductor substrate within an atomic layer deposition chamber;

b) heating the substrate to a temperature below 200°

C.;

c) introducing anhydrous hafnium nitrate into the chamber;

d) purging the chamber with nitrogen or inert gas; and

e) introducing a hydrating gas into the chamber, whereby a monolayer of hafnium oxide is deposited.

2. The method of claim 1, wherein the hydrating gas is water vapor, methanol or hydrogen.

3. The method of claim 1, wherein the substrate is heated to a temperature in the range of between 160 and 200°

C.

4. The method of claim 1, further comprising repeating the steps of introducing anhydrous hafnium nitrate into the chamber, purging the chamber, and introducing the hydrating gas into the chamber.

5. The method of claim 4, wherein the indicated steps are repeated until a hafnium oxide film with an equivalent oxide thickness of less than 20 angstroms is achieved.

14. The method of claim 3, wherein the substrate is heated to a temperature of approximately 170°

C.

15. The method of claim 3, wherein the substrate is heated to a temperature of approximately 180°

C.

6. A method of forming a high-k dielectric film on a substrate comprising the steps of:

a) providing a hydrogen passivated silicon surface on the semiconductor substrate within an atomic layer deposition chamber;

b) heating the substrate to a temperature below 200°

C.;

c) introducing anhydrous zirconium nitrate into the chamber;

d) purging the chamber with nitrogen; and

e) introducing a hydrating gas into the chamber, whereby a monolayer of zirconium oxide is deposited.

7. The method of claim 6, wherein the hydrating gas is water vapor, methanol or hydrogen.

8. The method of claim 6, wherein the substrate is heated to a temperature in the range of between 160 and 200°

C.

9. The method of claim 6, further comprising repeating the steps of introducing anhydrous zirconium nitrate into the chamber, purging the chamber, and introducing the hydrating gas into the chamber.

10. The method of claim 9, wherein the indicated steps are repeated until a zirconium oxide film with an equivalent oxide thickness of less than 20 angstroms is achieved.

16. The method of claim 8, wherein the substrate is heated to a temperature of approximately 170°

C.

17. The method of claim 8, wherein the substrate is heated to a temperature of approximately 180°

C.

11. A method of forming a nanolaminate, which comprises hafnium oxide and zirconium oxide, comprising the steps of:

a) providing a semiconductor substrate having a hydrogen passivated silicon surface within an atomic layer deposition chamber;

b) heating the substrate to a temperature below 200°

C.;

c) forming a layer of hafnium oxide by a process comprising the steps of;

(i) introducing anhydrous hafnium nitrate into the chamber;

(ii) purging the chamber;

(iii) introducing a hydrating gas into the chamber, whereby a monolayer of hafnium oxide is formed;

(iv) purging the chamber; and

d) forming a layer of zirconium oxide by a process comprising the step of;

(i) introducing anhydrous zirconium nitrate into the chamber;

(ii) purging the chamber; and

(iii) introducing a hydrating gas into the chamber, whereby a monolayer of zirconium oxide is formed; and

(iv) purging the chamber.

12. The method of claim 11, further comprising repeating the step of c) forming the layer of hafnium oxide until a desired thickness is reached.

13.The method of claim 11, further comprising repeating the step of d) forming the layer of zirconium oxide until a desired thickness is reached.

13. The method of claim 11, further comprising repeating the steps of c) forming the layer of hafnium oxide and d) forming the layer of zirconium oxide, whereby the nanolaminate of a desired total thickness is formed.

18. The method of claim 11, wherein the substrate is heated to a temperature of between 160 and 200°

C.