Transition metal alloys for use as a gate electrode and devices incorporating these alloys

• US 7,030,430 B2
• Filed: 08/15/2003
• Issued: 04/18/2006
• Est. Priority Date: 08/15/2003
• Status: Active Grant

• Current Assignee: Tahoe Research Limited (f/k/a Learndale Limited) (Vector Capital Corporation)
• Original Assignee: Intel Corporation
• Inventors: Chau, Robert S., Doczy, Mark, Lang, Teemu, Baxter, Nathan, Harkonen, Kari
• Primary Examiner(s): Wilson, Christian
• Assistant Examiner(s): Menz, Douglas M.
• Application Number:
  US10/641,848
• Publication Number:
  US 20050037557A1
• Time in Patent Office: 977 Days
• Field of Search: 257/249, 257/412, 257/454, 257/407
• US Class Current: 257/249
• CPC Class Codes: C04B 2235/722 Nitrogen content
• CPC Class Codes: C04B 2235/723 Oxygen content
• CPC Class Codes: C04B 35/5618 based on titanium aluminium carbides
• CPC Class Codes: C22C 14/00 Alloys based on titanium
• CPC Class Codes: C22C 16/00 Alloys based on zirconium
• CPC Class Codes: C22C 27/00 Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00
• CPC Class Codes: C22C 32/0084 carbon or graphite as the main non-metallic constituent
• CPC Class Codes: H01L 21/28088 the final conductor layer next to the insulator being a composite, e.g. TiN
• CPC Class Codes: H01L 21/82345 gate conductors with different gate conductor materials or different gate conductor implants, e.g. dual gate structures
• CPC Class Codes: H01L 21/823842 gate conductors with different gate conductor materials or different gate conductor implants, e.g. dual gate structures
• CPC Class Codes: H01L 29/4966 the conductor material next to the insulator being a composite material, e.g. organic material, TiN, MoSi2 H01L29/4908, H01L29/4983 take precedence
• CPC Class Codes: H01L 29/6659 with both lightly doped source and drain extensions and source and drain self-aligned to the sides of the gate, e.g. lightly doped drain [LDD] MOSFET, double diffused drain [DDD] MOSFET

Abstract

Embodiments of a transition metal alloy having an n-type or p-type work function that does not significantly shift at elevated temperature. The disclosed transition metal alloys may be used as, or form a part of, the gate electrode in a transistor. Methods of forming a gate electrode using these transition metal alloys are also disclosed.

Claims

1. A device comprising:

a substrate having a source region and a drain region formed therein;

an insulating layer disposed on the substrate and extending between the source and drain regions; and

a gate electrode overlying the insulating layer, the gate electrode formed of an alloy including

approximately 20 to 50 atomic percent of a transition metal, the transition metal selected from a group consisting of titanium, zirconium, tantalum, and hafnium,

approximately 30 to 60 atomic percent of carbon, and

up to approximately 20 atomic percent of aluminum.

2. The device of claim 1, wherein the alloy has a work function in a range of approximately 3.8 eV to 4.4 eV.

3. The device of claim 2, wherein the work function does not significantly shift at a temperature up to approximately 900°

Celsius.

4. The device of claim 2, wherein the source and drain regions comprise n-type regions and the substrate includes a p-type region underlying the source and drain regions.

5. The device of claim 1, wherein the gate electrode alloy does not react substantially with the insulating layer at a temperature up to approximately 900°

Celsius.

6. The device of claim 1, wherein the insulating layer comprises a material having a high dielectric constant.

7. The device of claim 1, wherein the high dielectric constant material comprises one of ZrO₂, HfO₂, and Al₂O₃.

8. The device of claim 1, further comprising up to 5 atomic percent of a residual material, the residual material comprising at least one of oxygen, nitrogen, and chloride.