Method for forming a V-shaped gate electrode in a semiconductor device, and the structure of the electrode

• US 5,804,474 A
• Filed: 04/04/1997
• Issued: 09/08/1998
• Est. Priority Date: 04/10/1996
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Monden, Koji, Yokoi, Yasushi, Sakaki, Hidehiko
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): Booth, Richard A.
• Application Number:
  US08/820,507
• Time in Patent Office: 522 Days
• Field of Search: 430/315, 430/329, 430/330, 438/585, 438/951, 438/182, 438/183, 438/949, 438/167
• US Class Current: 438/167
• CPC Class Codes: H01L 21/0272 for lift-off processes
• CPC Class Codes: H01L 21/28581 Deposition of Schottky electrodes
• CPC Class Codes: H01L 21/28587 characterised by the sectional shape, e.g. T, inverted T
• CPC Class Codes: H01L 29/66863 Lateral single gate transistors
• CPC Class Codes: Y10S 438/949 Energy beam treating radiation resist on semiconductor
• CPC Class Codes: Y10S 438/951 Lift-off

Abstract

A method for forming a V-shaped gate electrode on a semiconductor substrate includes the following steps: A first gate opening is formed in a first resist between a source and a drain formed on a semiconductor substrate, and dummy openings are formed near both sides of the first gate opening. By baking the first resist, convex portions thereof which rise steeply are formed between the first gate opening and the dummy openings. A second resist is formed to overlay the first resist convex portions and the first gate opening. The second resist is removed from the first gate opening, and a second gate opening larger than the first gate opening is formed in the second resist above the first gate opening. Metal for the V-shaped gate electrode is deposited through the second gate opening on the sides of the first resist convex portions rising steeply from the bottom of the first gate opening. A lift-off technique is performed to leave the V-shaped gate electrode by dissolving the first resist convex portions and the second resist.

Claims

1. A method for forming a V-shaped gate electrode on a semiconductor substrate, comprising the steps of:

forming a first resist covering said semiconductor substrate and a source and a drain formed thereon;

forming a first gate opening in said first resist between said source and said drain on said semiconductor substrate;

forming dummy openings in proximity to both sides of said first gate opening; and

depositing metal on said semiconductor substrate, while utilizing said first gate opening and said dummy openings to guide said depositing of metal, to form said V-shaped gate electrode.

6. A method for forming a V-shaped gate electrode according to claim 1, wherein said gate electrode has a rise angle of 45 degrees or more with respect to said semiconductor substrate.

7. A method for forming a V-shaped gate electrode according to claim 6, wherein said rise angle is 65 degrees or more.

2. A method for forming a V-shaped gate electrode on a semiconductor substrate, comprising the steps of:

forming a first gate opening on a first resist between a source and a drain formed on said semiconductor substrate, and forming dummy openings in proximity to both sides of said first gate opening;

forming first resist convex portions rising steeply between said first gate opening and said dummy openings by baking said first resist;

forming a second resist to overlay the first resist convex portions and said first gate opening;

removing said second resist above said first gate opening, and forming a second gate opening larger than said first gate opening in said second resist above said first gate opening;

depositing metal for said V-shaped gate electrode on the sides of the first resist convex portions rising steeply from the bottom of said first gate opening through said second gate opening; and

performing a lift-off technique for leaving said V-shaped gate electrode by dissolving the first resist convex portions and said second resist.

3. A method for forming a V-shaped gate electrode according to claim 2, wherein said first gate opening, formed between a pair of said first resist convex portions after said first resist is baked, is shaped so that said gate electrode, formed by deposition of metal on the sides of the first resist convex portions from the bottom of said first gate opening, is generally V-shaped.

4. A method for forming a V-shaped gate electrode according to claim 3, wherein said second resist is baked at a temperature lower than a temperature at which said first resist is baked.

5. A method for forming a V-shaped gate electrode according to claim 2, wherein said second resist is baked at a temperature lower than a temperature at which said first resist is baked.

8. A method for forming a V-shaped gate electrode according to claim 2, wherein said gate electrode has a rise angle of 45 degrees or more with respect to said semiconductor substrate.

9. A method for forming a V-shaped gate electrode according to claim 8, wherein said rise angle is 65 degrees or more.