Patent US4902647A successfully refreshed from Google Patents.
US4902647A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface modification using low energy ground state ion beams
Assignee: National Aeronautics and Space Administration
•
Filing: 1988-10-21
•
Granted: 1990-02-20
•
Expires: 2008-10-21
Abstract
Abstract A method of effecting modifications at the surfaces of materials using low energy ion beams of known quantum state, purity, flux and energy. The ion beam is obtained by bombarding ion-generating molecules with electrons which are also at low energy. The electrons used to bombard the ion generating molecules are separated from the ions thus obtained and the ion beam is directed at the material surface to be modified. Depending on the type of ion generating molecules used, different ions can be obtained for different types of surface modifications such as oxidation and diamond film formation.
Inventors
- 👤 Ara Chutjian
- 👤 Michael H. Hecht
- 👤 Otto J. Orient
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:19
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6306; H10P14/6308; H10P14/6309; H10N; H10N60/00; H10N60/01; H10N60/0884; H10P95/00; H10P95/90; H10P95/904; H10P14/69; H10P14/692; H10P14/6921; H10P14/69215; Y; Y10; Y10S; Y10S438/00; Y10S438/961
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
85 words
A method of effecting changes at the surface of a semiconductor material in the fabrication of semiconductor devices comprising the steps of: supplying a stream of molecules which will emit ions when bombarded with electrons; bombarding the stream of molecules with electrons which have been accelerated to sufficient energy to produce a beam composed of ions in the ground state; and directing the beam of ions in the ground state at the surface so as to effect changes at the surface without generating substantial heat.
Claim 2
Independent Claim
85 words
A method of effecting changes at the surface of a semiconductor material in the fabrication of semiconductor devices comprising the steps of: supplying a stream of molecules which will emit ions when bombarded with electrons; bombarding the stream of molecules with electrons which have been accelerated to sufficient energy to produce a beam composed of ions in the ground state; and directing the beam of ions in the ground state at the surface so as to effect changes at the surface without generating substantial heat.
Claim 3
Dependent Claim
27 words
A method as in claim 1 wherein the ions produced by bombardment of the molecules are accelerated to a selected energy before the ions reach the surface.
Claim 4
Dependent Claim
23 words
A method as in claim 2 wherein the energy level of the ions are selected within the range of 1 to 20 eV.
Claim 5
Dependent Claim
14 words
A method as in claim 3 wherein the surface is modified at room temperature.
Claim 6
Dependent Claim
30 words
A method as in claim 4 further comprising the step of separating the electrons used to bombard the molecules from the ion beam before the ion beam reaches the surface.
Claim 7
Dependent Claim
26 words
A method according to claim 5 wherein the electrons are separated from the ions by providing electrostatic plates to deflect the path of the ion beam.
Claim 8
Independent Claim
75 words
A method of oxidizing a surface of a semiconductor comprising the steps of: supplying a stream of molecules which will emit oxygen ions when bombarded with electrons; bombarding the stream of molecules with electrons which have been accelerated to sufficient energy to produce a beam of oxygen ions in the ground quantum state; and directing the beam of oxygen ions at the surface of the semiconductor material to oxidize the surface without generating substantial heat.
Claim 9
Independent Claim
75 words
A method of oxidizing a surface of a semiconductor comprising the steps of: supplying a stream of molecules which will emit oxygen ions when bombarded with electrons; bombarding the stream of molecules with electrons which have been accelerated to sufficient energy to produce a beam of oxygen ions in the ground quantum state; and directing the beam of oxygen ions at the surface of the semiconductor material to oxidize the surface without generating substantial heat.
Claim 10
Dependent Claim
36 words
A method as in claim 7 further comprising the step of separating the electrons used to bombard the molecules from the oxygen ion beam before the oxygen ion beam reaches the surface of the semiconductor material.
Claim 11
Dependent Claim
27 words
A method as in claim 8 further comprising the step of accelerating the oxygen ions to a selected energy before the oxygen ions reach the semiconductor surface.
Claim 12
Dependent Claim
33 words
A method as in claim 9 wherein the oxygen ions are substantially in the ground state and the energy of the oxygen ions is selected within the range of 1 to 20 eV.
Claim 13
Dependent Claim
15 words
A method as in claim 10 wherein the semiconductor material is oxidized at room temperature.
Claim 14
Dependent Claim
49 words
A method as in claim 11 wherein the surface of the semiconductor is exposed to the oxygen ion beam for a duration in the order of 30 minutes to form a layer of oxide of a thickness in the order of 20Å on the surface of the semiconductor material.
Claim 15
Dependent Claim
12 words
A method according to claim 11 wherein the molecules are nitric oxide.
Claim 16
Dependent Claim
22 words
A method according to claim 13 wherein the energy of the electrons is selected within the range of 1 to 15 eV.
References Cited (Backward Citations)
JPS5565901A
Cited
GB2059150A
Cited
US4351712A
Cited
JPS57111019A
Cited
US4541890A
Cited
JPS6134831A
Cited
JPS6187340A
Cited
CA1227289A
Cited
JPS62122040A
Cited
US4649273A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-19 | 1993-08-21 | 1994-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-19 | 1997-08-21 | 1998-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-19 | 2001-08-21 | 2002-02-20 | $7700.00 | Window Closed / Lapsed |