Patent US5849643A successfully refreshed from Google Patents.
US5849643A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gate oxidation technique for deep sub quarter micron transistors
Assignee: Advanced Micro Devices Inc
•
Filing: 1997-05-23
•
Granted: 1998-12-15
•
Expires: 2017-05-23
Abstract
Abstract A method of growing an oxide film in which the upper surface of a semiconductor substrate is cleaned and the semiconductor substrate is dipped into an acidic solution to remove any native oxide from the upper surface. The substrate is then directly transferred from the acidic solution to an oxidation chamber. The oxidation chamber initially contains an inert ambient maintained at a temperature of less than approximately 500° C. The transfer is accomplished without substantially exposing the substrate to oxygen thereby preventing the formation of a native oxide film on the upper surface of the substrate. Thereafter, a fluorine terminated upper surface is formed on the semiconductor substrate. The temperature within the chamber is then ramped from the first temperature to a second or oxidizing temperature if approximately 700° C. to 850° C. The presence of the fluorine terminated upper surface substantially prevents oxidation of the semiconductor substrate during the temperature ramp. A silicon-oxide film such as silicon dioxide is then grown on the fluorine terminated upper surface of the semiconductor substrate by introducing an oxidizing ambient into the chamber. After the formation or growth of the silicon-oxide, polysilicon is deposited on the silicon oxide film.
Inventors
- 👤 Mark C. Gilmer
- 👤 Mark I. Gardner
- 👤 Daniel Kadosh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:08
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01332; H10D64/01336; H10D64/0134; H10D64/01346; H10D64/60; H10D64/66; H10D64/68; Y; Y10; Y10S; Y10S438/00; Y10S438/905; Y10S438/906
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
164 words
A method of growing an oxide, comprising: providing a semiconductor substrate, wherein said semiconductor substrate comprises silicon; cleaning an upper surface of said semiconductor substrate; dipping said semiconductor substrate into an acidic solution to remove any native oxide from said upper surface; transferring said semiconductor substrate from said acidic solution to an oxidation chamber containing an inert ambient maintained at a temperature of less than approximately 500° C., wherein said transferring occurs without substantially exposing said semiconductor substrate to oxygen to prevent a native oxide from forming on said upper surface; forming a fluorine terminated upper surface of said semiconductor substrate; ramping said chamber from said first temperature to a second temperature in the range of approximately 700° to 850° C. wherein said fluorine terminated upper surface substantially prevents oxidation of said semiconductor substrate during said ramping; growing silicon-oxide on said fluorine terminated upper surface of said semiconductor substrate by introducing an oxidizing ambient into said chamber; and depositing polysilicon on said silicon-oxide film.
Claim 2
Independent Claim
164 words
A method of growing an oxide, comprising: providing a semiconductor substrate, wherein said semiconductor substrate comprises silicon; cleaning an upper surface of said semiconductor substrate; dipping said semiconductor substrate into an acidic solution to remove any native oxide from said upper surface; transferring said semiconductor substrate from said acidic solution to an oxidation chamber containing an inert ambient maintained at a temperature of less than approximately 500° C., wherein said transferring occurs without substantially exposing said semiconductor substrate to oxygen to prevent a native oxide from forming on said upper surface; forming a fluorine terminated upper surface of said semiconductor substrate; ramping said chamber from said first temperature to a second temperature in the range of approximately 700° to 850° C. wherein said fluorine terminated upper surface substantially prevents oxidation of said semiconductor substrate during said ramping; growing silicon-oxide on said fluorine terminated upper surface of said semiconductor substrate by introducing an oxidizing ambient into said chamber; and depositing polysilicon on said silicon-oxide film.
Claim 3
Dependent Claim
21 words
The method of claim 1, wherein said semiconductor substrate comprises a p-type silicon epitaxial layer formed over a p+ silicon bulk.
Claim 4
Dependent Claim
23 words
The method of claim 2, wherein a resistivity of said p-type epitaxial layer is in the range of approximately 10 to 15 Ω-cm.
Claim 5
Dependent Claim
77 words
The method of claim 1, wherein the step of cleaning said upper surface comprises: immersing the wafer in a first solution comprising H 2 O, NH 4 OH, and H 2 O 2 maintained at a temperature in the range of approximately 75° to 85° C.; and immersing the wafer in a second solution comprising H 2 O, HCl, and H 2 O 2 maintained at a temperature in the range of approximately 75° to 85° C.
Claim 6
Dependent Claim
31 words
The method of claim 1, wherein the step of dipping comprising immersing said semiconductor substrate into an acidic solution comprising H 2 O and HF in a ratio of approximately 40:1.
Claim 7
Dependent Claim
11 words
The method of claim 1, wherein said inert ambient comprises Argon.
Claim 8
Dependent Claim
53 words
The method of claim 1, wherein the step of forming said fluorine terminated upper surface comprises cycling a chamber ambient between a first ambient comprising an inert species and a second ambient comprising fluorine while maintaining said ambient at said first temperature to form a fluorine terminated upper surface of said semiconductor substrate.
Claim 9
Dependent Claim
20 words
The method of claim 7, wherein said first ambient comprises Argon and wherein said second ambient comprises NF 3 .
Claim 10
Dependent Claim
35 words
The method of claim 1, wherein said oxidizing ambient comprises species selected from the group consisting of N 2 , NO, N 2 O, NH 3 , NF 3 , O 2 , and HCl.
Claim 11
Dependent Claim
33 words
The method of claim 1, wherein the step of depositing said polysilicon is performed in situ with the step of growing said silicon-oxide thereby preventing said semiconductor substrate from being exposed to atmosphere.
Claim 12
Independent Claim
182 words
A method of growing an oxide film on an upper surface of a semiconductor substrate; providing a semiconductor substrate, wherein said semiconductor substrate comprises silicon and wherein an upper surface of said semiconductor substrate is substantially free of native oxide; loading said semiconductor substrate into an oxidation chamber maintained at a first temperature of less than approximately 500° C., wherein said loading occurs without substantially exposing said semiconductor substrate to oxygen to prevent a native oxide from forming on said upper surface; cycling said chamber ambient between a first ambient comprising an inert species and a second ambient comprising fluorine while maintaining said chamber at said first temperature to form a fluorine terminated upper surface of said semiconductor substrate; ramping said chamber from said first temperature to a second temperature in the range of approximately 700° to 850° C., wherein said fluorine terminated upper surface substantially prevents oxidation of said semiconductor substrate during said ramping; growing silicon-oxide on said fluorine terminated upper surface of said semiconductor substrate by introducing an oxidizing ambient into said chamber; and depositing polysilicon on said silicon-oxide film.
Claim 13
Independent Claim
182 words
A method of growing an oxide film on an upper surface of a semiconductor substrate; providing a semiconductor substrate, wherein said semiconductor substrate comprises silicon and wherein an upper surface of said semiconductor substrate is substantially free of native oxide; loading said semiconductor substrate into an oxidation chamber maintained at a first temperature of less than approximately 500° C., wherein said loading occurs without substantially exposing said semiconductor substrate to oxygen to prevent a native oxide from forming on said upper surface; cycling said chamber ambient between a first ambient comprising an inert species and a second ambient comprising fluorine while maintaining said chamber at said first temperature to form a fluorine terminated upper surface of said semiconductor substrate; ramping said chamber from said first temperature to a second temperature in the range of approximately 700° to 850° C., wherein said fluorine terminated upper surface substantially prevents oxidation of said semiconductor substrate during said ramping; growing silicon-oxide on said fluorine terminated upper surface of said semiconductor substrate by introducing an oxidizing ambient into said chamber; and depositing polysilicon on said silicon-oxide film.
Claim 14
Dependent Claim
39 words
The method of claim 11, wherein said semiconductor substrate comprises a p-type epitaxial layer formed on a p+ silicon bulk and wherein a resistivity of said p-type epitaxial layer is in the range of approximately 10 to 15 Ω-cm.
Claim 15
Dependent Claim
49 words
The method of claim 11, wherein said oxidation chamber comprises an inert ambient during the step of loading said semiconductor substrate and further wherein said loading is accomplished without exposing said semiconductor substrate to an oxidizing ambient, whereby native oxide is substantially prevented from forming on said semiconductor substrate.
Claim 16
Dependent Claim
11 words
The method of claim 11, wherein said first ambient comprises argon.
Claim 17
Dependent Claim
12 words
The method of claim 11, wherein said second ambient further comprises nitrogen.
Claim 18
Dependent Claim
13 words
The method of claim 15, wherein said second ambient comprises NF 3 .
Claim 19
Dependent Claim
28 words
The method of claim 11, wherein the step of depositing said polysilicon comprises thermally decomposing silane at a temperature in the range of approximately 580° to 650° C.
Claim 20
Dependent Claim
22 words
The method of claim 17, wherein said depositing of said polysilicon is performed in situ with said growth of said silicon-oxide film.
References Cited (Backward Citations)
US5030319A
Cited
US5009926A
Cited
US5314780A
Cited
US5707500A
Cited
US5635053A
Cited
US5735962A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-12-14 | 2002-06-15 | 2002-12-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-14 | 2006-06-15 | 2006-12-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-14 | 2010-06-15 | 2010-12-15 | $7700.00 | Window Closed / Lapsed |