Patent US4350201A successfully refreshed from Google Patents.
Patent EP0428283A2 successfully refreshed from Google Patents.
EP0428283A2
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EP
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Method for local oxidation of silicon
Assignee: Advanced Micro Devices Inc
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Filing: 1990-10-26
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Granted: —
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Expires: 2010-10-26
Abstract
Abstract A process of forming field oxide regions using a field oxidation performed in a dry oxidation environment in a temperature equal to or greater than approximately 1000°C. The dry oxidation reduces or eliminates the formation of Kooi ribbons, and the high temperature field oxidation allows the field oxide to flow, thereby reducing physical stresses normally associated with field oxidation performed at temperatures below 1000°C. The high temperature field oxidation also greatly reduces the ratio of the length of the bird's beaks formed during the field oxidation to the thickness of the field oxide, allowing smaller active regions to be formed. The thinner field oxide regions, in turn, make it possible to perform the field implant after the field oxidation, thereby avoiding the lateral encroachment problem and controlling source to drain or drain to source punch-through under the gate. Further, the high temperature field oxidation allows the well implant drive and the field oxidation to be performed simultaneously.
Inventors
- 👤 Yowjuang Liu
- 👤 Steven W. Longcor
- 👤 Jih-Chang Lien
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 11:33
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/61; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/0125; H10W10/0126; H10W10/0127; H10W10/10; H10W10/13
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
65 words
A method of forming thick oxide regions in a semiconductor substrate, comprising the steps of: (a) providing a barrier layer overlying the substrate; (b) providing a non-oxidizable masking layer overlying portions of the barrier oxide layer corresponding to active regions; and (c) oxidizing the substrate in an environment including dry oxygen at a temperature equal to or greater than approximately 1000°C after said step (b).
Claim 2
Independent Claim
65 words
A method of forming thick oxide regions in a semiconductor substrate, comprising the steps of: (a) providing a barrier layer overlying the substrate; (b) providing a non-oxidizable masking layer overlying portions of the barrier oxide layer corresponding to active regions; and (c) oxidizing the substrate in an environment including dry oxygen at a temperature equal to or greater than approximately 1000°C after said step (b).
Claim 3
Dependent Claim
42 words
A method according to claim 1, wherein: said step (a) comprises providing a barrier layer having a thickness x; said step (b) comprises providing a masking layer having a thickness y; and the ratio y/x is equal to or greater than 5.
Claim 4
Dependent Claim
56 words
A method according to claim 1, wherein: said step (a) comprises providing a barrier layer having a thickness x, where x is greater than approximately 50Å; said step (b) comprises providing a masking layer having a thickness y, where y is greater than approximately 1000Å; and the ratio y/x is equal to or greater than 10.
Claim 5
Dependent Claim
19 words
A method according to claim 1, wherein said step (c) comprises oxidizing the substrate at a temperature ranging f°C.
Claim 6
Dependent Claim
20 words
A method according to claim 1, further comprising the step (d) of performing a field implant after said step (c).
Claim 7
Dependent Claim
33 words
A method according to claim 1, wherein said step (c) forms a field oxide, further comprising the step (d) of performing a field implant through the field oxide formed in said step (c).
Claim 8
Dependent Claim
52 words
A method according to claim 1, further comprising the step of (d) implanting a dopant having a conductivity type opposite to the conductivity type of the substrate in a portion of the substrate prior to said step (c), wherein said step (c) comprises driving the well implant and concurrently oxidizing the substrate.
Claim 9
Dependent Claim
21 words
A method according to claim 1, wherein said step (c) comprises oxidizing the substrate in an environment comprising O₂ and HCl.
Claim 10
Dependent Claim
53 words
A method according to claim 1, wherein said step (c) comprises the sequential sub-steps of: (i) oxidizing the substrate in an environment comprising O₂ and HCl at a temperature less than approximately 1050°C; and (ii) oxidizing the substrate in an environment comprising O₂ and HCl at a temperature greater than approximately 1100 °C.
Claim 11
Dependent Claim
82 words
An improved method of forming field oxide regions in a substrate includes the steps of providing a barrier layer overlying the substrate, providing a non-oxidizable masking layer overlying portions of the barrier layer corresponding to selected first regions of the substrate, and oxidizing second regions of the substrate to forms field oxide regions, the improvement comprising the step of: (a) oxidizing the second regions of the substrate in an environment including dry oxygen at a temperature equal to or greater than 1000°C.
Claim 12
Dependent Claim
82 words
An improved method of forming field oxide regions in a substrate includes the steps of providing a barrier layer overlying the substrate, providing a non-oxidizable masking layer overlying portions of the barrier layer corresponding to selected first regions of the substrate, and oxidizing second regions of the substrate to forms field oxide regions, the improvement comprising the step of: (a) oxidizing the second regions of the substrate in an environment including dry oxygen at a temperature equal to or greater than 1000°C.
Claim 13
Dependent Claim
57 words
A method according to claim 10, wherein the improvement further comprises performing said step (a) as the sequential sub-steps of: (i) oxidizing the substrate in an environment comprising O₂ and HCl at a temperature less than approximately 1050°C; and (ii) oxidizing the substrate in an environment comprising O₂ and HCl at a temperature greater than approximately 1100°C.
Claim 14
Dependent Claim
51 words
A method according to claim 10, wherein the improvement further comprises the steps of: (b) providing a barrier layer comprising an oxide of silicon having a thickness x; (c) providing a masking layer comprising silicon nitride having a thickness y, where the ratio y/x is equal to or greater than 10.
Claim 15
Dependent Claim
23 words
A method according to claim 10, wherein the improvement further comprises the step of: (b) performing a field implant after said step (a).
Claim 16
Dependent Claim
28 words
A method according to claim 10, wherein the improvement further comprises the step of: (b) performing a field implant through the field oxide formed in said step (a).
Claim 17
Dependent Claim
50 words
A method according to claim 10, wherein the improvement further comprises the step of (b) implanting a well dopant in a selected portion of the substrate prior to said step (a), wherein said step (a) comprises concurrently oxidizing the substrate and driving the well dopant implanted in said step (b).
Claim 18
Independent Claim
92 words
A method of forming field oxide (FOX) regions in a semiconductor substrate, comprising the steps of: (a) implanting a well dopant in a selected well region of the substrate; (b) providing a barrier oxide layer overlying the substrate; (c) providing a nitride layer overlying portions of the barrier oxide corresponding to active regions of the substrate; and (d) heating the substrate in an environment including dry oxygen and HCl at a temperature equal to or greater than 1000°C to oxidize the substrate, thereby forming field oxide regions and driving the well implant.
Claim 19
Independent Claim
92 words
A method of forming field oxide (FOX) regions in a semiconductor substrate, comprising the steps of: (a) implanting a well dopant in a selected well region of the substrate; (b) providing a barrier oxide layer overlying the substrate; (c) providing a nitride layer overlying portions of the barrier oxide corresponding to active regions of the substrate; and (d) heating the substrate in an environment including dry oxygen and HCl at a temperature equal to or greater than 1000°C to oxidize the substrate, thereby forming field oxide regions and driving the well implant.
Claim 20
Dependent Claim
43 words
A method according to claim 16, wherein: said step (b) comprises providing a barrier oxide layer having a thickness x; said step (c) comprises providing a nitride layer having a thickness y; and the ratio y/x is equal to or greater than 10.
Claim 21
Dependent Claim
53 words
A method according to claim 16, wherein: said step (b) comprises providing a barrier oxide layer having a thickness x, where x is approximately 50-250Å; said step (c) comprises providing a nitride layer having a thickness y, where y is approximately 1000-3000Å; and the ratio y/x is equal to or greater than 10.
Claim 22
Dependent Claim
20 words
A method according to claim 16, further comprising the step (e) of performing a field implant after said step (d).
Claim 23
Dependent Claim
26 words
A method according to claim 16, further comprising the step (e) of performing a field implant through the field oxide regions formed in said step (d).
Claim 24
Independent Claim
217 words
A method of fabricating a plurality of field effect transistors in a semiconductor substrate having a conductivity type, the field effect transistors being electrically isolated by field oxide regions, comprising the sequential steps of: (a) implanting a dopant of the opposite conductivity type to form at least one well in the substrate; (b) providing a barrier oxide layer overlying the substrate; (c) providing a nitride layer overlying portions of the barrier oxide corresponding to active regions of the substrate, at least one active region being located in the well; (d) oxidizing the substrate in an environment comprising O₂ and HCl at a temperature less than approximately 1050°C and then oxidizing the substrate in an environment comprising O₂ and HCl at a temperature greater than approximately 1100°C to form field oxide regions and to drive the dopant implanted in said step (a); (e) removing the nitride layer; (f) implanting a field dopant in the substrate, said implant being performed through the field oxide regions; (g) providing a plurality of gates overlying respective ones of the active regions of the substrate; and (h) implanting source and drain regions in each of the active regions utilizing the corresponding gates as a masks so that each pair of source and drain regions are spaced apart and define a channel region therebetween.
Claim 25
Independent Claim
217 words
A method of fabricating a plurality of field effect transistors in a semiconductor substrate having a conductivity type, the field effect transistors being electrically isolated by field oxide regions, comprising the sequential steps of: (a) implanting a dopant of the opposite conductivity type to form at least one well in the substrate; (b) providing a barrier oxide layer overlying the substrate; (c) providing a nitride layer overlying portions of the barrier oxide corresponding to active regions of the substrate, at least one active region being located in the well; (d) oxidizing the substrate in an environment comprising O₂ and HCl at a temperature less than approximately 1050°C and then oxidizing the substrate in an environment comprising O₂ and HCl at a temperature greater than approximately 1100°C to form field oxide regions and to drive the dopant implanted in said step (a); (e) removing the nitride layer; (f) implanting a field dopant in the substrate, said implant being performed through the field oxide regions; (g) providing a plurality of gates overlying respective ones of the active regions of the substrate; and (h) implanting source and drain regions in each of the active regions utilizing the corresponding gates as a masks so that each pair of source and drain regions are spaced apart and define a channel region therebetween.
Claim 26
Dependent Claim
38 words
A method according to claim 21, further comprising the step of: (i) etching the nitride and the field oxide regions to reduce the step height of the field oxide after said step (d) and before said step (e).
Claim 27
Dependent Claim
57 words
A method according to claim 21, further comprising the step of: (i) etching the nitride and the field oxide regions with a plasma etchant, including CF₄, which etches the nitride and the field oxide at approximately the same rate to reduce the step height of the field oxide after said step (d) and before said step (e).
Claim 28
Dependent Claim
43 words
A method according to claim 21, wherein: said step (b) comprises providing a barrier oxide layer having a thickness x; said step (c) comprises providing a nitride layer having a thickness y; and the ratio y/x is equal to or greater than 10.
Claim 29
Dependent Claim
53 words
A method according to claim 21, wherein: said step (b) comprises providing a barrier oxide layer having a thickness x, where x is approximately 50-250Å; said step (c) comprises providing a nitride layer having a thickness y, where y is approximately 1000-3000Å; and the ratio y/x is equal to or greater than 10.
Claim 30
Dependent Claim
29 words
A method according to claim 21, wherein said step (f) comprises implanting a field dopant in active regions defined by the field oxide regions formed in said step (d).
References Cited (Backward Citations)
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