Method of forming a field effect transistor using conductive masking material

• US 7,271,064 B2
• Filed: 08/24/2005
• Issued: 09/18/2007
• Est. Priority Date: 01/31/2002
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Sandhu, Sukesh, Bicksler, Andrew R.
• Primary Examiner(s): PIZARRO CRESPO, MARCOS D
• Application Number:
  US11/211,915
• Publication Number:
  US 20050282339A1
• Time in Patent Office: 755 Days
• Field of Search: 438257-267, 438584-596
• US Class Current: 438/265
• CPC Class Codes: H01L 21/28247 passivation or protection of the electrode, e.g. using re-oxidation
• CPC Class Codes: H01L 29/40114 the electrodes comprising a conductor-insulator-conductor-insulator-semiconductor structure
• CPC Class Codes: H01L 29/66825 with a floating gate H01L29/6684 takes precedence
• CPC Class Codes: H01L 29/7881 Programmable transistors with only two possible levels of programmation H01L29/7888 takes precedence

Abstract

The invention includes methods of forming field effect transistors. In one implementation, a method of forming a field effect transistor having a gate comprising a conductive metal or metal compound received over conductively doped semiconductive material includes forming transistor gate semiconductive material into a gate line over a semiconductive material channel region. The gate line includes semiconductive material sidewalls. The semiconductive material sidewalls of the gate line are oxidized. After the oxidizing, at least one of a conductive metal or metal compound is formed in electrical connection with the transistor gate semiconductive material to comprise a substantially coextensive elongated portion of a final construction of the gate line of the field effect transistor being formed.

Claims

1. A method of forming a field effect transistor having a gate comprising a conductive metal or metal compound received over conductively doped semiconductive material, the method comprising:

forming transistor gate semiconductive material into a gate line over a semiconductive material channel region, the gate line comprising semiconductive material sidewalls;

forming conductive masking material over the transistor gate semiconductive material;

oxidizing the semiconductive material sidewalls of the gate line;

after the oxidizing, depositing insulative material over the gate line;

after the depositing, removing the insulative material and the conductive masking material effective to expose the gate line; and

after the removing, forming at least one of a conductive metal or metal compound in electrical connection with the transistor gate semiconductive material to comprise a substantially coextensive elongated portion of a final construction of the gate line of the field effect transistor being formed, the forming the at least one of a conductive metal or metal compound to comprise a substantially coextensive elongated portion of a final construction of the gate line of the field effect transistor being formed comprising deposition of said at least one and patterning and subtractively etching of said at least one.

2. The method of claim 1 wherein the patterning and subtractively etching of said at least one forms the at least one of a conductive metal or metal compound to be laterally wider than the semiconductive material of the transistor gate line.

3. The method of claim 1 further comprising conducting a highest dose source/drain implant for the transistor prior to the oxidizing.

4. The method of claim 1 wherein the field effect transistor gate line does not comprise a floating gate.

5. The method of claim 1 wherein the removing exposes the transistor gate semiconductive material.

6. The method of claim 1 wherein the removing comprises polishing.

7. The method of claim 1 wherein the conductive masking material is formed prior to depositing the insulative material.

8. The method of claim 1 wherein the conductive masking material is formed prior to the oxidizing.

9. The method of claim 1 wherein the oxidizing is effective to grow oxide on the semiconductive material sidewalls to have a maximum thickness of at least 30 Angstroms.

10. The method of claim 1 wherein the forming of the at least one of a conductive metal or metal compound comprises forming a conductive metal.

11. The method of claim 1 wherein the forming of the at least one of a conductive metal or metal compound comprises forming a conductive metal compound.

12. A method of forming a field effect transistor having a gate comprising a conductive metal or metal compound received over conductively doped semiconductive material, the method comprising:

forming transistor gate semiconductive material over a semiconductive material channel region;

forming conductive masking material over the transistor gate semiconductive material;

forming the transistor gate semiconductive material and the conductive masking material into a gate line, the gate line comprising semiconductive material sidewalls;

oxidizing the semiconductive material sidewalls of the gate line;

after the oxidizing, depositing insulative material over the gate line;

after the depositing, removing the insulative material effective to expose the gate line; and

after the removing, forming at least one of a conductive metal or metal compound in electrical connection with the transistor gate semiconductive material to comprise a substantially coextensive elongated portion of a final construction of the gate line of the field effect transistor being formed.

13. The method of claim 12 wherein the forming the at least one of a conductive metal or metal compound to comprise a substantially coextensive elongated portion of a final construction of the gate line of the field effect transistor being formed comprises deposition of said at least one and polishing of said at least one.

14. The method of claim 12 wherein the forming the at least one of a conductive metal or metal compound to comprise a substantially coextensive elongated portion of a final construction of the gate line of the field effect transistor being formed comprises selective formation of said at least one on the transistor gate semiconductive material.

15. The method of claim 12 wherein the removing exposes the transistor gate semiconductive material.

16. The method of claim 12 wherein the removing comprises polishing.

17. The method of claim 12 wherein the field effect transistor gate line does not comprise a floating gate.

18. The method of claim 12 wherein the oxidizing is effective to grow oxide on the semiconductive material sidewalls to have a maximum thickness of at least 30 Angstroms.

19. The method of claim 12 wherein the forming of the at least one of a conductive metal or metal compound comprises forming a conductive metal.

20. The method of claim 12 wherein the forming of the at least one of a conductive metal or metal compound comprises forming a conductive metal compound.