Low-temperature growth high-quality ultra-thin praseodymium gate dieletrics Number:7,064,058 from the United States Patent and Trademark Office (PTO) owispatent A praseodymium (Pr) gate oxide and method of fabricating same that produces a high-quality and ultra-thin equivalent oxide thickness as compared to conventional SiO.sub.2 gate oxides are provided. The Pr gate oxide is thermodynamically stable so that the oxide reacts minimally with a silicon substrate or other structures during any later high temperature processing stages. The process shown is performed at lower temperatures than the prior art, which further inhibits reactions with the silicon substrate or other structures. Using a thermal evaporation technique to deposit a Pr layer to be oxidized, the underlying substrate surface smoothness is preserved, thus providing improved and more consistent electrical properties in the resulting gate oxide.<H praseodymium, temperature, Low, temperature, 7064058.html, Patent, pto, 7064058

Title: Low-temperature growth high-quality ultra-thin praseodymium gate dieletrics

Abstract: A praseodymium (Pr) gate oxide and method of fabricating same that produces a high-quality and ultra-thin equivalent oxide thickness as compared to conventional SiO.sub.2 gate oxides are provided. The Pr gate oxide is thermodynamically stable so that the oxide reacts minimally with a silicon substrate or other structures during any later high temperature processing stages. The process shown is performed at lower temperatures than the prior art, which further inhibits reactions with the silicon substrate or other structures. Using a thermal evaporation technique to deposit a Pr layer to be oxidized, the underlying substrate surface smoothness is preserved, thus providing improved and more consistent electrical properties in the resulting gate oxide.

Patent Number: 7,064,058 Issued on 06/20/2006 to Ahn, et al.

Inventors: Ahn; Kie Y. (Chappaqua, NY); Forbes; Leonard (Corvallis, OR)
Assignee: Micron Technology, Inc. (Boise, ID)

Appl. No.: 768597

Filed: January 30, 2004

Related U.S. Patent Documents


Application Number	Filing Date	Patent Number	Issue Date
10027315	Dec., 2001	6900122

Current U.S. Class: 438/635

Current International Class: H01L 21/4763 (20060101)

Field of Search: 438/635

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Primary Examiner: Sarkar; Asok Kumar
Attorney, Agent or Firm: Schwegman, Lundberg, Woessner & Kluth, P.A.

Parent Case Text

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 10/027,315 filed on Dec. 20, 2001, now U.S. Pat. No. 6,900,122, which is incorporated herein by reference.

Claims

What is claimed is:

1. A method comprising: thermal evaporation depositing a praseodymium (Pr) layer on a surface on a substrate; and oxidizing the Pr layer to form an oxide on the surface, the oxide including a praseodymium oxide layer, wherein thermal evaporation depositing the Pr layer and oxidizing the Pr layer are performed at substrate temperatures that inhibit formation of unwanted silicides and oxides.

2. The method of claim 1, wherein thermal evaporation depositing the Pr layer includes thermal evaporation depositing by electron beam evaporation to form the Pr layer as an amorphous Pr layer.

3. The method of claim 2, wherein electron beam evaporation depositing the Pr layer includes electron beam evaporating a 99.9999% pure Pr target.

4. The method of claim 1, wherein thermal evaporation depositing the Pr layer includes thermal evaporation depositing at an approximate substrate temperature range of 150 400.degree. C.

5. The method of claim 1, wherein oxidizing the Pr layer includes oxidizing at a substrate temperature of approximately 400.degree. C.

6. The method of claim 1, wherein oxidizing the Pr layer includes oxidizing with atomic oxygen.

7. The method of claim 1, wherein oxidizing the Pr layer includes oxidizing using a krypton (Kr)/oxygen (O.sub.2) mixed plasma process having a plasma density above 10.sup.12/cm.sup.3.

8. The method of claim 1, wherein the method includes forming the oxide layer to have an equivalent oxide thickness (EOT) of less than 2 nm.

9. A method comprising: thermal evaporation depositing a praseodymium (Pr) layer on a surface on a substrate, the substrate having a substrate temperature ranging from about 150.degree. C. to about 400.degree. C.; and oxidizing the Pr layer using a krypton (Kr)/oxygen (O.sub.2) mixed plasma process to form an oxide on the surface, the oxide including a Pr.sub.2O.sub.3 layer, wherein thermal evaporation depositing the Pr layer and oxidizing the Pr layer are performed at substrate temperatures that inhibit formation of unwanted silicides and oxides.

10. The method of claim 9, wherein thermal evaporation depositing the metal layer includes thermal evaporation depositing by electron beam evaporation.

11. The method of claim 10, wherein oxidizing the Pr layer using a krypton (Kr)/oxygen (O.sub.2) mixed plasma process includes oxidizing the Pr layer using a krypton (Kr)/oxygen (O.sub.2) mixed plasma process at an electron temperature below 1.3 eV.

12. The method of claim 9, wherein the method further includes conducting the Kr/O.sub.2 mixed plasma process using a microwave power density of about 5 W/cm.

13. The method of claim 9, wherein thermal evaporation depositing a praseodym