US4270972A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for controlled doping semiconductor material with highly volatile dopant
Assignee: Boeing North American Inc
•
Filing: 1980-03-31
•
Granted: 1981-06-02
•
Expires: 2000-03-31
Abstract
Abstract In conjunction with the use of a float-zone crystal grower for doping silicon, a holder for temporarily storing pellets of solid dopant is disposed outside the housing of the crystal grower. A rotatable cylinder in the holder is provided with a plurality of chambers into which charges of varying amounts of dopant may be stored. A separate charge of dopant is propelled by inert gas under pressure into the melt zone of a silicon rod in the crystal grower upon the occurrence of a specified event such as passage of time or translation of the silicon rod. The apparatus and method are particularly applicable to doping with a highly volatile dopant such as indium.
Inventors
- 👤 Allen G. Crouse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:05
CPC Classifications
C; C30; C30B; C30B13/00; C30B13/08; C30B13/10; Y; Y10; Y10S; Y10S117/00; Y10S117/906; Y10S118/00; Y10S118/90; Y10S438/00; Y10S438/914; Y10S438/925
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
218 words
A method of doping semiconductor material with a highly volatile dopant in a float-zone crystal grower, the crystal grower comprising a gas impermeable housing, an induction heating coil disposed within the housing, and means for transporting a rod of the semiconductor material through the coil, said method comprising the steps of: (a) disposing a holder for storing solid pieces of said dopant outside the housing, wherein said holder comprises a rotatable cylinder having a plurality of distinct chambers; (b) providing feed means for propelling the dopant from one of said chambers through an exit port of said holder and into the housing in the vicinity of the coil whereby said dopant may enter a melted zone of said rod of semiconductor material; (c) distributing a plurality of solid pieces of said dopant into said chambers; (d) rotating said cylinder until a selected chamber is positioned adjacent said exit port; (e) delivering inert gas under pressure into the interior of said holder and into said selected chamber; (f) expelling the dopant from said selected chamber through said feed means into the melted zone of said rod of semiconductor material; (g) rotating said cylinder until a different selected chamber is positioned adjacent said exit port; and (h) repeating steps (e) through (g) until said rod of semiconductor material is doped.
Claim 2
Independent Claim
218 words
A method of doping semiconductor material with a highly volatile dopant in a float-zone crystal grower, the crystal grower comprising a gas impermeable housing, an induction heating coil disposed within the housing, and means for transporting a rod of the semiconductor material through the coil, said method comprising the steps of: (a) disposing a holder for storing solid pieces of said dopant outside the housing, wherein said holder comprises a rotatable cylinder having a plurality of distinct chambers; (b) providing feed means for propelling the dopant from one of said chambers through an exit port of said holder and into the housing in the vicinity of the coil whereby said dopant may enter a melted zone of said rod of semiconductor material; (c) distributing a plurality of solid pieces of said dopant into said chambers; (d) rotating said cylinder until a selected chamber is positioned adjacent said exit port; (e) delivering inert gas under pressure into the interior of said holder and into said selected chamber; (f) expelling the dopant from said selected chamber through said feed means into the melted zone of said rod of semiconductor material; (g) rotating said cylinder until a different selected chamber is positioned adjacent said exit port; and (h) repeating steps (e) through (g) until said rod of semiconductor material is doped.
Claim 3
Dependent Claim
25 words
The method recited in claim 1 further comprising the step of waiting until a specified event occurs before proceeding from step (f) to step (g).
Claim 4
Dependent Claim
19 words
The method recited in claim 2 wherein said specified event is the passage of a predetermined interval of time.
Claim 5
Dependent Claim
26 words
The method recited in claim 2 wherein said specified event is the displacement of a portion of said rod of semiconductor material over a predetermined distance.
References Cited (Backward Citations)
US2768914A
Cited
US2851341A
Cited
US3040727A
Cited
US3065062A
Cited
US3141848A
Cited
US3175975A
Cited
US3804682A
Cited
US3954416A
Cited
US4040890A
Cited
US4110586A
Cited
US4126509A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-06-01 | 1984-12-01 | 1985-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-01 | 1988-12-01 | 1989-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-01 | 1992-12-01 | 1993-06-02 | $7700.00 | Window Closed / Lapsed |