Patent US4514440A successfully refreshed from Google Patents.
US4514440A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spin-on dopant method
Assignee: Honeywell International Inc
•
Filing: 1983-12-12
•
Granted: 1985-04-30
•
Expires: 2003-12-12
Abstract
Abstract A single step method for boron dopant diffusion implementing both deposition and drive-in diffusions in one furnace process is provided. By using a spin-on dopant in a diffusion furnace with pyrogenic steam and thermal ramping capabilities, sheet resistivities and penetrations to a precision and accuracy of 4% with one furnace step are achievable. The one step method disclosed circumvents the use of two furnace processes to achieve a typical p-type diffusion which requires a deposition in a furnace set at one temperature followed by a drive in diffusion in a furnace set at a second temperature after deglazing in a hydrofluoric acid. Also attainable by the one step process disclosed are resistivity uniformities better than those with the two furnace processes.
Inventors
- 👤 Bruce H. Justice
- 👤 Robert F. Aycock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:24
CPC Classifications
H; H10; H10P; H10P32/00; H10P32/10; H10P32/14; H10P32/1408; H10P32/141; C; C30; C30B; C30B31/00; C30B31/02; H10P32/1404; H10P32/17; H10P32/171; Y; Y10; Y10S; Y10S438/00; Y10S438/914; Y10S438/92
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
168 words
A single furnace method for boron dopant deposition and diffusion of a p-type semiconductor substrates comprising: (a) applying a dopant layer to said semiconductor substrate from a gaseous dopant source until an initial resistivity in the range of about 4 to about 200 ohms per square is attained; (b) producing a conducting interfacial layer between said semiconductor substrate and said dopant layer by maintaining a temperature of at least about 900° C.; (c) removing said dopant source by maintaining a steam atmosphere of at least about 900° C.; (d) thermal ramping said treated semiconductor substrate to a drive in temperature for the doping in an atmosphere selected from inert, oxidizing or steam; (e) oxidizing excess silicon boride by subjecting said treated semiconductor substrate for about 5 to 20 minutes in a steam atmosphere at a temperature of the order of 1050° C. to 1250° C.; and (f) driving the boron present in said interfacial layer to the desired depth and resistivity level in an inert or oxidizing atmosphere.
Claim 2
Dependent Claim
168 words
A single furnace method for boron dopant deposition and diffusion of a p-type semiconductor substrates comprising: (a) applying a dopant layer to said semiconductor substrate from a gaseous dopant source until an initial resistivity in the range of about 4 to about 200 ohms per square is attained; (b) producing a conducting interfacial layer between said semiconductor substrate and said dopant layer by maintaining a temperature of at least about 900° C.; (c) removing said dopant source by maintaining a steam atmosphere of at least about 900° C.; (d) thermal ramping said treated semiconductor substrate to a drive in temperature for the doping in an atmosphere selected from inert, oxidizing or steam; (e) oxidizing excess silicon boride by subjecting said treated semiconductor substrate for about 5 to 20 minutes in a steam atmosphere at a temperature of the order of 1050° C. to 1250° C.; and (f) driving the boron present in said interfacial layer to the desired depth and resistivity level in an inert or oxidizing atmosphere.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein step (c) is conducted in an atmosphere of burned hydrogen.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein step (e) is conducted in an atmosphere of burned hydrogen.
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein the dopant applied in step (a) is effected by a spin-on process.
Claim 6
Dependent Claim
19 words
The method of claim 1 wherein the temperature employed in step (b) is between 900° C. and 1150° C.
Claim 7
Dependent Claim
15 words
The method of claim 1 wherein the atmosphere employed in step (c) is burned hydrogen.
Claim 8
Dependent Claim
17 words
The method of claim 1 wherein the temperature in step (c) is 900° C. to 1150° C.
Claim 9
Dependent Claim
15 words
The method of claim 1 wherein the atmosphere employed in step (e) is burned hydrogen.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-04-29 | 1988-10-29 | 1989-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-29 | 1992-10-29 | 1993-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-29 | 1996-10-29 | 1997-04-30 | $7700.00 | Window Closed / Lapsed |