Patent US5194397A successfully refreshed from Google Patents.
US5194397A
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Method for controlling interfacial oxide at a polycrystalline/monocrystalline silicon interface
Assignee: International Business Machines Corp
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Filing: 1991-06-05
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Granted: 1993-03-16
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Expires: 2011-06-05
Abstract
Abstract A method of controlling the interfacial oxygen concentration of a monocrystalline/polycrystalline emitter includes the steps of: passivating the monocrystalline silicon surface by immersing the wafer in a diluted HF acid solution; transferring the wafer into a high vacuum environment; heating the wafer to between 400° and 700° C.; exposing the monocrystalline silicon surface to a gas having a partial pressure of oxygen of between 10 -5 to 1 Torr for between 1 and 100 minutes; and, depositing polysilicon onto the monocrystalline silicon surface.
Inventors
- 👤 Robert K. Cook
- 👤 Ronald W. Knepper
- 👤 Subodh K. Kulkarni
- 👤 Russell C. Lange
- 👤 Paul A. Ronsheim
- 👤 Seshadri Subbanna
- 👤 Manu J. Tejwani
- 👤 Bob H. Yun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:45
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6306; H10P14/6308; H10P14/6309; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0113; H10P14/6322; H10P14/65; H10P14/6502; H10P14/6508; H10P32/00; H10P32/10; H10P32/14; H10P32/1408; H10P32/141; H10P32/1412; H10P32/17; H10P32/171; Y; Y10; Y10S; Y10S148/00; Y10S148/017; Y10S148/124; Y10S438/00; Y10S438/974
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
160 words
A method of forming a bipolar transistor with a predetermined gain and having a low resistance, polycrystalline/monocrystalline silicon emitter contact interface, comprising the steps of: a) determining a first concentration of interfacial oxygen at the polycrystalline/monocrystalline silicon interface necessary to provide the specified gain according to a predetermined schedule correlating transistor gain to the concentration of interfacial oxygen at the polycrystalline/monocrystalline silicon interface; b) passivating the monocrystalline silicon with hydrogen; c) heating the monocrystalline silicon to a predetermined temperature; d) exposing the monocrystalline silicon for a predetermined length of time to a gas having a predetermined partial pressure of oxygen in order to oxidize a portion of the monocrystalline silicon in order to provide said first concentration of interfacial oxygen at the polycrystalline/monocrystalline silicon interface in accordance with said predetermined schedule; and, e) depositing polycrystalline silicon onto the monocrystalline silicon, wherein said first concentration of interfacial oxygen yields a specific emitter contact resistance of less than 100 ohms-um 2 .
Claim 2
Independent Claim
160 words
A method of forming a bipolar transistor with a predetermined gain and having a low resistance, polycrystalline/monocrystalline silicon emitter contact interface, comprising the steps of: a) determining a first concentration of interfacial oxygen at the polycrystalline/monocrystalline silicon interface necessary to provide the specified gain according to a predetermined schedule correlating transistor gain to the concentration of interfacial oxygen at the polycrystalline/monocrystalline silicon interface; b) passivating the monocrystalline silicon with hydrogen; c) heating the monocrystalline silicon to a predetermined temperature; d) exposing the monocrystalline silicon for a predetermined length of time to a gas having a predetermined partial pressure of oxygen in order to oxidize a portion of the monocrystalline silicon in order to provide said first concentration of interfacial oxygen at the polycrystalline/monocrystalline silicon interface in accordance with said predetermined schedule; and, e) depositing polycrystalline silicon onto the monocrystalline silicon, wherein said first concentration of interfacial oxygen yields a specific emitter contact resistance of less than 100 ohms-um 2 .
Claim 3
Dependent Claim
37 words
A method of forming a bipolar transistor with a specified gain and having a low resistance, polycrystalline/monocrystalline silicon emitter according to claim 1, wherein step b) comprises immersing the substrate in a first solution comprised of HF.
Claim 4
Dependent Claim
39 words
A method of forming a bipolar transistor with a specified gain and having a low resistance, polycrystalline/monocrystalline silicon emitter according to claim 2, wherein step b) comprises immersing the substrate in a first solution comprised of dilute 10:1 HF.
Claim 5
Dependent Claim
34 words
A method of forming a bipolar transistor with a specified gain and having a low resistance, polycrystalline/monocrystalline silicon emitter according to claim 1, wherein said predetermined temperature is between 400 and 700 degrees centigrade.
Claim 6
Dependent Claim
35 words
A method of forming a bipolar transistor with a specified gain and having a low resistance, polycrystalline/monocrystalline silicon emitter according to claim 1, wherein said predetermined amount of time is between 1 and 100 minutes.
Claim 7
Dependent Claim
35 words
A method of forming a bipolar transistor with a specified gain and having a low resistance, polycrystalline/monocrystalline silicon emitter according to claim 1, wherein said predetermined partial pressure is between 1×10 -5 and 1 Torr.
Claim 8
Dependent Claim
46 words
A method of forming a bipolar transistor with a specified gain and having a low resistance, polycrystalline/monocrystalline silicon emitter according to claim 1, after step b) further comprising the step of: substantially evacuating the atmosphere surrounding the substrate in order to inhibit oxidation of the substrate.
Claim 9
Independent Claim
96 words
A method of forming a device onto a monocrystalline silicon substrate comprising the steps of: a) passivating the monocrystalline silicon with hydrogen; b) heating the substrate to a first specified temperature; c) keeping the substrate at said first specified temperature for a specified length of time in order to oxidize a portion of the substrate, wherein said specified amount of time is between 15 and 300 seconds; d) evacuating the atmosphere around the substrate to a specified partial pressure; e) heating the substrate to a second specified temperature; and, f) depositing polycrystalline silicon onto the substrate.
Claim 10
Independent Claim
96 words
A method of forming a device onto a monocrystalline silicon substrate comprising the steps of: a) passivating the monocrystalline silicon with hydrogen; b) heating the substrate to a first specified temperature; c) keeping the substrate at said first specified temperature for a specified length of time in order to oxidize a portion of the substrate, wherein said specified amount of time is between 15 and 300 seconds; d) evacuating the atmosphere around the substrate to a specified partial pressure; e) heating the substrate to a second specified temperature; and, f) depositing polycrystalline silicon onto the substrate.
Claim 11
Independent Claim
93 words
A method of forming a device onto a monocrystalline silicon substrate comprising the steps of: a) passivating the monocrystalline silicon with hydrogen; b) heating the substrate to a first specified temperature, wherein said heating takes between 30 and 90 seconds; c) keeping the substrate at said first specified temperature for a specified length of time in order to oxidize a portion of the substrate; d) evacuating the atmosphere around the substrate to a specified partial pressure; e) heating the substrate to a second specified temperature; and, f) depositing polycrystalline silicon onto the substrate.
Claim 12
Independent Claim
93 words
A method of forming a device onto a monocrystalline silicon substrate comprising the steps of: a) passivating the monocrystalline silicon with hydrogen; b) heating the substrate to a first specified temperature, wherein said heating takes between 30 and 90 seconds; c) keeping the substrate at said first specified temperature for a specified length of time in order to oxidize a portion of the substrate; d) evacuating the atmosphere around the substrate to a specified partial pressure; e) heating the substrate to a second specified temperature; and, f) depositing polycrystalline silicon onto the substrate.
Claim 13
Independent Claim
118 words
A method of forming a device onto a monocrystalline silicon substrate comprising the steps of: a) passivating the monocrystalline silicon by immersing the substrate in a first solution comprised of 10:1 dilute HF; b) heating, the substrate to a temperature on the order of 535 degrees centigrade, wherein said heating takes between 30 and 90 seconds; c) keeping the substrate at said temperature for on the order of 45 seconds in order to oxidize a portion of the substrate; d) evacuating the atmosphere around the substrate to a partial pressure on the order of 10 mTorr; e) heating the substrate to a temperature on the order of 620 degrees centigrade; and, f) depositing polycrystalline silicon onto the substrate.
Claim 14
Independent Claim
118 words
A method of forming a device onto a monocrystalline silicon substrate comprising the steps of: a) passivating the monocrystalline silicon by immersing the substrate in a first solution comprised of 10:1 dilute HF; b) heating, the substrate to a temperature on the order of 535 degrees centigrade, wherein said heating takes between 30 and 90 seconds; c) keeping the substrate at said temperature for on the order of 45 seconds in order to oxidize a portion of the substrate; d) evacuating the atmosphere around the substrate to a partial pressure on the order of 10 mTorr; e) heating the substrate to a temperature on the order of 620 degrees centigrade; and, f) depositing polycrystalline silicon onto the substrate.
Claim 15
Dependent Claim
28 words
A method of forming a device onto a monocrystalline silicon substrate according to claim 10, wherein the time between steps a) and b) is less than 12 hours.
Claim 16
Independent Claim
104 words
A method of forming a device onto a monocrystalline silicon substrate comprising the steps of: a) passivating the monocrystalline silicon with hydrogen; b) heating the substrate to a first specified temperature; c) keeping the substrate at said predetermined temperature for a predetermined length of time in order to oxidize a portion of the substrate; d) evacuating the atmosphere around the substrate to a first predetermined partial pressure; e) heating the substrate to a second predetermined temperature; f) exposing the substrate to HCL gas; g) evacuating the atmosphere around the substrate to a second predetermrned partial pressure; and, g) depositing polycrystalline silicon onto the substrate.
Claim 17
Independent Claim
104 words
A method of forming a device onto a monocrystalline silicon substrate comprising the steps of: a) passivating the monocrystalline silicon with hydrogen; b) heating the substrate to a first specified temperature; c) keeping the substrate at said predetermined temperature for a predetermined length of time in order to oxidize a portion of the substrate; d) evacuating the atmosphere around the substrate to a first predetermined partial pressure; e) heating the substrate to a second predetermined temperature; f) exposing the substrate to HCL gas; g) evacuating the atmosphere around the substrate to a second predetermrned partial pressure; and, g) depositing polycrystalline silicon onto the substrate.
Claim 18
Dependent Claim
29 words
A method of forming a device onto a monocrystalline silicon substrate according to claim 12, wherein step a) comprises immersing the substrate in a first solution comprised of HF.
Claim 19
Dependent Claim
31 words
A method of forming a device onto a monocrystalline silicon substrate according to claim 12, wherein step a) comprises immersing the substrate in a first solution comprised of 10:1 dilute HF.
Claim 20
Dependent Claim
28 words
A method of forming a device onto a monocrystalline silicon substrate according to claim 12, wherein said first, specified temperature is on the order of 535 degrees centigrade.
Claim 21
Dependent Claim
28 words
A method of forming a device onto a monocrystalline silicon substrate according to claim 12, wherein said specified amount of time is on the order of 45 seconds.
Claim 22
Dependent Claim
27 words
A method of forming a device onto a monocrystalline silicon substrate according to claim 12, wherein said specified partial pressure is on the order of 10 mTorr.
Claim 23
Dependent Claim
30 words
A method of forming a device onto a monocrystalline silicon substrate according to claim 12, wherein said first and second specified partial pressures are on the order of 10 mTorr.
Claim 24
Dependent Claim
28 words
A method of forming a device onto a monocrystalline silicon substrate according to claim 12, wherein the time between steps a) and b) is less than 12 hours.
Claim 25
Dependent Claim
24 words
A method of forming a device onto a monocrystalline silicon substrate according to claim 12, wherein step b) takes between 30 and 90 seconds.
Claim 26
Dependent Claim
28 words
A method of forming a device onto a monocrystalline silicon substrate according to claim 12, wherein said second specified temperature is on the order of 620 degrees centigrade.
Claim 27
Independent Claim
140 words
A method of forming a device onto a monocrystalline silicon substrate comprising the steps of: a) passivating the monocrystalline silicon by immersing the substrate in a first solution comprised of 10:1 dilute HF; b) heating, the substrate to a temperature on the order of 535 degrees centigrade, over a period of between 30 and 90 seconds; c) keeping the substrate at said temperature for on the order of 45 seconds in order to oxidize a portion of the substrate; d) evacuating the atmosphere around the substrate to a partial pressure on the order of 10 mTorr; e) heating, the substrate to a temperature on the order of 620 degrees centigrade; f) exposing the substrate to a HCL gas; g) evacuating the atmosphere around the substrate to on the order of 10 mTorr; and, h) depositing polycrystalline silicon onto the substrate.
Claim 28
Independent Claim
140 words
A method of forming a device onto a monocrystalline silicon substrate comprising the steps of: a) passivating the monocrystalline silicon by immersing the substrate in a first solution comprised of 10:1 dilute HF; b) heating, the substrate to a temperature on the order of 535 degrees centigrade, over a period of between 30 and 90 seconds; c) keeping the substrate at said temperature for on the order of 45 seconds in order to oxidize a portion of the substrate; d) evacuating the atmosphere around the substrate to a partial pressure on the order of 10 mTorr; e) heating, the substrate to a temperature on the order of 620 degrees centigrade; f) exposing the substrate to a HCL gas; g) evacuating the atmosphere around the substrate to on the order of 10 mTorr; and, h) depositing polycrystalline silicon onto the substrate.
Claim 29
Independent Claim
173 words
A method of forming a bipolar transistor with a specified gain and having a low resistance, polycrystalline/monocrystalline silicon emitter contact interface, comprising the steps of: a) determining a first concentration of interfacial oxygen at the polycrystalline/monocrystalline silicon interface necessary to provide: 1) the specified gain according to a specified schedule correlating transistor gain to the concentration of interfacial oxygen at the polycrystalline/monocrystalline silicon interface and 2) an emitter contact resistance of less than 100 ohms-um 2 according to a specified schedule correlating emitter contact resistance to the concentration of interfacial oxygen at the polycrystalline/monocrystalline silicon interface; b) passivating the monocrystalline silicon with hydrogen; c) heating the monocrystalline silicon to a specified temperature; d) exposing the monocrystalline silicon for a specified length of time to a gas having a specified partial pressure of oxygen in order to oxidize a portion of the monocrystalline silicon in order to provide said first concentration of interfacial oxygen at the polycrystalline/monocrystallie silicon interface in accordance with said specified schedules; and, e) depositing polycrystalline silicon onto the monocrystalline silicon.
Claim 30
Independent Claim
173 words
A method of forming a bipolar transistor with a specified gain and having a low resistance, polycrystalline/monocrystalline silicon emitter contact interface, comprising the steps of: a) determining a first concentration of interfacial oxygen at the polycrystalline/monocrystalline silicon interface necessary to provide: 1) the specified gain according to a specified schedule correlating transistor gain to the concentration of interfacial oxygen at the polycrystalline/monocrystalline silicon interface and 2) an emitter contact resistance of less than 100 ohms-um 2 according to a specified schedule correlating emitter contact resistance to the concentration of interfacial oxygen at the polycrystalline/monocrystalline silicon interface; b) passivating the monocrystalline silicon with hydrogen; c) heating the monocrystalline silicon to a specified temperature; d) exposing the monocrystalline silicon for a specified length of time to a gas having a specified partial pressure of oxygen in order to oxidize a portion of the monocrystalline silicon in order to provide said first concentration of interfacial oxygen at the polycrystalline/monocrystallie silicon interface in accordance with said specified schedules; and, e) depositing polycrystalline silicon onto the monocrystalline silicon.
References Cited (Backward Citations)
JPH0210820A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-03-15 | 1996-09-14 | 1997-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-03-15 | 2000-09-14 | 2001-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-03-15 | 2004-09-14 | 2005-03-16 | $7700.00 | Window Closed / Lapsed |