Methods of forming field effect transistors including floating gate field effect transistors

• US 20040203209A1
• Filed: 04/29/2004
• Published: 10/14/2004
• Est. Priority Date: 01/31/2002
• Status: Active Grant

• Current Assignee: Andrew R. Bicksler, Sukesh Sandhu
• Original Assignee: Andrew R. Bicksler, Sukesh Sandhu
• Inventors: Sandhu, Sukesh, Bicksler, Andrew R.
• Granted Patent: US 7,112,491 B2
• Time in Patent Office: Days
• 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

1-30. -30 (canceled).

31. 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;

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;

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.

32. The method of claim 31 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.

33. The method of claim 31 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 subtractively patterning and etching of said at least one.

34. The method of claim 31 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.

35. The method of claim 31 wherein the removing exposes the transistor gate semiconductive material.

36. The method of claim 31 wherein the removing comprises polishing.

37. The method of claim 31 wherein the removing increases planarity of an outer surface of the insulative material from what is was prior to said removing.

38. The method of claim 31 further comprising forming masking material over the transistor gate semiconductive material, the removing comprising removing the masking material.

39. The method of claim 31 further comprising forming masking material over the transistor gate semiconductive material prior to depositing the insulative material, the removing comprising also removing the masking material.

40. The method of claim 31 further comprising forming masking material over the transistor gate semiconductive material prior to the oxidizing, the removing comprising also removing the masking material.

41. The method of claim 31 wherein the oxidizing is effective to grow oxide on the semiconductive material sidewalls to have a maximum thickness of at least 30 Angstroms.

42. The method of claim 31 wherein the field effect transistor gate comprises a floating gate field effect transistor gate, the method further comprising forming the gate line to comprise a plurality of floating gates underlying a control gate line, the oxidizing also oxidizing sidewalls of the floating gates.

43. The method of claim 31 wherein the field effect transistor gate does not comprise a floating gate.