Method to control the interfacial layer for deposition of high dielectric constant films

• US 6,875,677 B1
• Filed: 09/30/2003
• Issued: 04/05/2005
• Est. Priority Date: 09/30/2003
• Status: Expired due to Fees

• Current Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ono, Yoshi, Conley, John F. Jr.
• Primary Examiner(s): THAI, LUAN C
• Application Number:
  US10/677,035
• Publication Number:
  US 20050070079A1
• Time in Patent Office: 553 Days
• Field of Search: 438/585, 438/287, 438/197
• US Class Current: 438/585
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/45553 characterized by the use of precursors specially adapted for ALD
• CPC Class Codes: H01L 21/02175 characterised by the metal H01L21/02197 takes precedence
• 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 21/02194 the material containing more than one metal element
• 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 21/02304 formation of intermediate layers, e.g. buffer layers, layers to improve adhesion, lattice match or diffusion barriers
• CPC Class Codes: H01L 21/3141 Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/31645 Deposition of Hafnium oxides, e.g. HfO2

Abstract

Methods of forming an interfacial layer on a hydrogen-passivated substrate are provided. These methods utilize atomic layer deposition techniques incorporating metal nitrate-based precursors, such as hafnium nitrate or zirconium nitrate, without introducing a hydrating agent, or oxidizing agent, such as water, during the formation of the interfacial layer. Also provided are methods of forming high-k films, by first forming an interfacial layer on the surface of a hydrogen-passivated substrate, and then depositing one, or more, high-k dielectric films.

Claims

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

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

b) forming an interfacial layer by heating the substrate to a temperature below 200 degrees Celsius and introducing anhydrous hafnium nitrate into the chamber without introducing a hydrating gas, or an additional oxidizing gas, during the formation of the interfacial layer; and

c) forming a high-k film overlying the interfacial layer.

2. The method of claim 1, wherein the substrate has a silicon surface.

3. The method of claim 1, wherein the substrate is heated to a temperature in the range of approximately 30 to 200°

C. during formation of the interfacial layer.

4. The method of claim 1, wherein forming the interfacial layer cycles anhydrous hafnium nitrate with a nitrogen purge.

5. The method of claim 1, wherein the step of forming a high-k film further comprises repeating the steps of:

introducing a hafnium-containing precursor into the chamber, purging the chamber, introducing H₂O into the chamber, and purging the chamber until a desired film thickness is achieved.

6. The method of claim 5, wherein the hafnium-containing precursor is anhydrous hafnium nitrate, hafnium chloride, or hafnium(tmhd)_x.

7. The method of claim 1, wherein the step of forming a high-k film overlying the interfacial layer further comprises repeating the steps of:

introducing a HfCl₄ precursor into the chamber, purging the chamber, introducing Hf(NO₃)₄ into the chamber, and purging the chamber until a desired film thickness is achieved.

8. The method of claim 1, wherein the step of forming a high-k film forms a high-k metal oxide film selected from the group consisting of ZrO₂, Gd₂O₃, La₂O₃, CeO₂, TiO₂, Y₂O₃, Ta₂O₅, Al₂O₃, HfAlO_x, ZrAlO_x, and HfZrO_x.

9. The method of claim 1, wherein the step of forming a high-k film forms a multilayer film comprising alternating layers of metal oxide films selected from the group consisting of ZrO₂, Gd₂O₃, La₂O₃, CeO₂, TiO₂, Y₂O₃, Ta₂O₅, Al₂O₃, HfAlO_x, ZrAlO_x, and HfZrO_x.

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

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

b) exposing the hydrogen passivated surface to a metal nitrate containing precursor at a temperature below the thermal decomposition temperature for the precursor without a hydrating gas, or an oxidizing gas, to produce self-limiting high-k interfacial layer; and

c) repeating the steps of exposing the surface to a metal-containing precursor, purging the chamber, exposing the surface to a hydrating gas, oxidizing gas, or precursor, and purging to deposit additional high-k material.

11. The method of claim 10, wherein the metal nitrate containing precursor has the formula M(NO₃)_x, where M is a metal selected from the group consisting of Hf, Zr, Gd, La, Ce, Ti, Y, Ta, and Al;

and x is the valence of M.

12. The method of claim 10, wherein the additional high-k material is the same material as the interfacial layer.

13. The method of claim 10, wherein the additional high-k material is different than the interfacial layer.