US6337246B1
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Method for inhibiting tunnel oxide growth at the edges of a floating gate during semiconductor device processing
Assignee: Monterey Research LLC
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Filing: 2001-04-02
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Granted: 2002-01-08
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Expires: 2021-04-02
Abstract
Abstract A method for making a ULSI MOSFET chip includes forming a MOSFET gate stack on a substrate, with a tunnel oxide layer being sandwiched between the gate stack and substrate. To prevent thickening of the tunnel oxide layer into a “gate edge lifting” profile during subsequent oxidation-causing steps, at least one protective barrier film is deposited or grown over the gate stack and tunnel oxide layer immediately after gate stack formation. Then, subsequent steps, including forming source and drain regions for the gate stack, can be undertaken without causing thickening of the tunnel oxide layer.
Inventors
- 👤 Daniel Sobek
- 👤 Timothy Thurgate
- 👤 Carl R. Huster
- 👤 Tuan Duc Pham
- 👤 Mark T. Ramsbey
- 👤 Sameer S. Haddad
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:33
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/031; H10D64/035
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
214 words
A method of making a gate stack semiconductor device, comprising: forming at least one transistor gate over a semiconductor substrate; forming at least one tunnel oxide layer disposed between the gate and the substrate, the at least one tunnel oxide layer defining at least one edge extending between the substrate and the at least one gate; forming a source region and a drain region in the substrate below the at least one gate; forming at least one inner barrier film covering at least the edge of the at least one tunnel oxide layer, said at least one inner barrier film having a uniform thickness in a range of 20 to 200 angstroms, said at least one inner barrier film comprising at least one material selected from a group consisting essentially of: stoichiometric silicon nitride (Si 3 N 4 ), silicon dioxide (SiO 2 ), and silicon oxynitride (SiON); and forming an outer barrier film covering said at least one inner barrier film, said outer barrier film having a uniform thickness in a range of 20 to 200 angstroms, said outer barrier film comprising silicon-rich silicon nitride (Si 3+n N 4 ), said at least one inner barrier film and said outer barrier film, together, preventing formation of “bird's beak” structures during subsequent oxidation steps.
Claim 2
Independent Claim
214 words
A method of making a gate stack semiconductor device, comprising: forming at least one transistor gate over a semiconductor substrate; forming at least one tunnel oxide layer disposed between the gate and the substrate, the at least one tunnel oxide layer defining at least one edge extending between the substrate and the at least one gate; forming a source region and a drain region in the substrate below the at least one gate; forming at least one inner barrier film covering at least the edge of the at least one tunnel oxide layer, said at least one inner barrier film having a uniform thickness in a range of 20 to 200 angstroms, said at least one inner barrier film comprising at least one material selected from a group consisting essentially of: stoichiometric silicon nitride (Si 3 N 4 ), silicon dioxide (SiO 2 ), and silicon oxynitride (SiON); and forming an outer barrier film covering said at least one inner barrier film, said outer barrier film having a uniform thickness in a range of 20 to 200 angstroms, said outer barrier film comprising silicon-rich silicon nitride (Si 3+n N 4 ), said at least one inner barrier film and said outer barrier film, together, preventing formation of “bird's beak” structures during subsequent oxidation steps.
Claim 3
Dependent Claim
23 words
The method of claim 1 , wherein the inner barrier film has a thickness of between fifty angstroms and one hundred fifty angstroms.
Claim 4
Dependent Claim
30 words
The method of claim 1 , wherein said inner barrier film is thermally grown in the temperature range between seven hundred fifty degrees Celsius and one thousand fifty degrees Celsius.
Claim 5
Dependent Claim
32 words
The method of claim 1 , wherein said inner barrier film is deposited using chemical vapor deposition in the temperature range between three hundred fifty degrees Celsius and nine hundred degrees Celsius.
Claim 6
Dependent Claim
40 words
The method of claim 1 , wherein said inner barrier film is stoichiometric silicon nitride deposited using low pressure chemical vapor deposition at a temperature in the range of seven hundred twenty-five degrees Celsius to eight hundred twenty-five degrees Celsius.
Claim 7
Dependent Claim
22 words
The method of claim 1 , wherein said outer barrier film has a thickness of between fifty and one hundred fifty angstroms.
Claim 8
Dependent Claim
29 words
The method of claim 1 , wherein said outer barrier film is thermally grown in the temperature range between seven hundred fifty degrees Celsius and nine hundred degrees Celsius.
Claim 9
Dependent Claim
32 words
The method of claim 1 , wherein said outer barrier film is deposited using chemical vapor deposition in the temperature range between three hundred fifty degrees Celsius and nine hundred degrees Celsius.
Claim 10
Dependent Claim
41 words
The method of claim 1 , wherein said outer barrier film is silicon rich silicon nitride deposited using low pressure chemical vapor deposition at a temperature in the range of seven hundred twenty-five degrees Celsius to eight hundred twenty-five degrees Celsius.
Claim 11
Independent Claim
200 words
A method of making a semiconductor device comprising: forming at least one transistor gate on at least one tunnel oxide layer having at least one exposed side surface extending between the at least one transistor gate and a substrate; forming a source region and a drain region in the substrate below the at least one tunnel oxide layer; and forming at least one inner barrier film covering at least the edge of the at least one tunnel oxide layer, said at least one inner barrier film having a uniform thickness in the range of 20 to 200 angstroms, said at least one inner barrier film comprising at least one material selected from a group consisting essentially of: stoichiometric silicon nitride (Si 3 N 4 ), silicon dioxide (SiO 2 ), and silicon oxynitride (SiON); and forming an outer barrier film covering said at least one inner barrier film, said outer barrier film having a uniform thickness in a range of 20 to 200 angstroms, said outer barrier film comprising silicon-rich silicon nitride (Si 3+n N 4 ), said at least one inner barrier film and said outer barrier film, together, preventing formation of “bird's beak” structures during subsequent oxidation steps.
Claim 12
Independent Claim
200 words
A method of making a semiconductor device comprising: forming at least one transistor gate on at least one tunnel oxide layer having at least one exposed side surface extending between the at least one transistor gate and a substrate; forming a source region and a drain region in the substrate below the at least one tunnel oxide layer; and forming at least one inner barrier film covering at least the edge of the at least one tunnel oxide layer, said at least one inner barrier film having a uniform thickness in the range of 20 to 200 angstroms, said at least one inner barrier film comprising at least one material selected from a group consisting essentially of: stoichiometric silicon nitride (Si 3 N 4 ), silicon dioxide (SiO 2 ), and silicon oxynitride (SiON); and forming an outer barrier film covering said at least one inner barrier film, said outer barrier film having a uniform thickness in a range of 20 to 200 angstroms, said outer barrier film comprising silicon-rich silicon nitride (Si 3+n N 4 ), said at least one inner barrier film and said outer barrier film, together, preventing formation of “bird's beak” structures during subsequent oxidation steps.
Claim 13
Dependent Claim
53 words
The method of claim 10 , wherein said inner barrier film is from the group of stoichiometric silicon nitride (Si 3 N 4 ), silicon dioxide (SiO 2 ), and silicon oxynitride (SiON), deposited using chemical vapor deposition in the temperature range between three hundred fifty degrees Celsius and nine hundred degrees Celsius.
Claim 14
Dependent Claim
45 words
The method of claim 10 , wherein said inner barrier film is stoichiometric silicon nitride (Si 3 N 4 ) deposited using low pressure chemical vapor deposition at a temperature in the range of seven hundred twenty-five degrees Celsius to eight hundred twenty-five degrees Celsius.
Claim 15
Independent Claim
169 words
A method of making a gate stack semiconductor device comprising: forming at least one transistor gate over a semiconductor substrate; forming at least one tunnel oxide layer disposed between the gate and the substrate, the at least one tunnel oxide layer defining at least one edge extending between the substrate and the at least one gate; forming at least one inner barrier film covering at least the edge of the at least one tunnel oxide layer, said at least one inner barrier film having a uniform thickness in the range of 20 to 200 angstroms, said inner barrier film comprising stoichiometric silicon nitride (Si 3 N 4 ); and forming an outer barrier film covering the inner barrier film, said outer barrier film having a thickness range of 20 to 200 angstroms, said outer barrier film comprising silicon-rich silicon nitride (Si 3+n N 4 ); and said at least one inner barrier film and said outer barrier film, together, preventing formation of “bird's beak” structures during subsequent oxidation steps.
Claim 16
Independent Claim
169 words
A method of making a gate stack semiconductor device comprising: forming at least one transistor gate over a semiconductor substrate; forming at least one tunnel oxide layer disposed between the gate and the substrate, the at least one tunnel oxide layer defining at least one edge extending between the substrate and the at least one gate; forming at least one inner barrier film covering at least the edge of the at least one tunnel oxide layer, said at least one inner barrier film having a uniform thickness in the range of 20 to 200 angstroms, said inner barrier film comprising stoichiometric silicon nitride (Si 3 N 4 ); and forming an outer barrier film covering the inner barrier film, said outer barrier film having a thickness range of 20 to 200 angstroms, said outer barrier film comprising silicon-rich silicon nitride (Si 3+n N 4 ); and said at least one inner barrier film and said outer barrier film, together, preventing formation of “bird's beak” structures during subsequent oxidation steps.
References Cited (Backward Citations)
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