US3718502A
Expired / Lapsed
US
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Enhancement of diffusion of atoms into a heated substrate by bombardment
Assignee: Individual
•
Filing: 1969-10-15
•
Granted: 1973-02-27
•
Expires: 1989-10-15
Abstract
Abstract This invention describes a method of enhancing the diffusion of atomic species carried on the surface of a solid substrate into the substrate by elevating the temperature of the substrate to permit atoms and vacancies to propagate and then creating vacancies in selected regions of the substrate through bombardment by a beam of protons or other particles, said bombard-ment acting to enhance diffusion of the surface atom species into the substrate at said regions.
Inventors
- 👤 J Gibbons
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 20:40
CPC Classifications
H; H10; H10P; H10P34/00; H10P34/40; H10D; H10D99/00; H10P32/00; H10P95/00
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
25 words
The method as in claim 1 wherein said temperature is below the temperature which would produce significant diffusion of atomic species in the solid substrate.
Claim 2
Dependent Claim
46 words
The method as in claim 2 in which said selected atom species at a surface of the substrate is provided by the additional step of predepositing on said surface a layer of material containing the selected atom species which is to be diffused into the substrate.
Claim 3
Dependent Claim
22 words
The method as in claim 2 wherein said substrate is silicon and said predetermined temperature is in the range of 450* -700*C.
Claim 4
Dependent Claim
23 words
The method as in claim 2 wherein said substrate is germanium and the elevated temperature is in the range of 360* - 500*C.
Claim 5
Dependent Claim
19 words
The method as in claim 3 wherein said predeposited layer is deposited only over selected areas of the surface.
Claim 6
Dependent Claim
65 words
The method as in claim 2 including additionally providing a mask having one or more openings on said surface whereby to intercept particles and prevent the formation of lattice vacancies in the substrate beneath the mask and permit particles to pass through said openings to bombard the substrate and form lattice vacancies in the region of said openings by dislodging atoms from their lattice positions.
Claim 7
Dependent Claim
18 words
The method as in claim 2 wherein selected areas are bombarded by focusing and directing the particle beam.
Claim 8
Dependent Claim
19 words
The method as in claim 2 wherein said particle beam comprises a proton beam having energies above 1 keV.
Claim 9
Dependent Claim
22 words
The method as in claim 1 wherein the damage previously existing in the semiconductor is annealed on account of the enhanced diffusion.
Claim 10
Dependent Claim
21 words
The method as in claim 10 wherein the damage is produced by introducing the atomic species using the ion implantation technique.
Claim 11
Dependent Claim
26 words
The method as in claim 10 wherein the damage is produced during the formation of an oxide layer or other protective coating on said semiconductor surface.
Claim 12
Dependent Claim
29 words
The method as in claim 10 wherein a protective layer is applied over said semiconductor to inhibit the escape of atomic species from the surface during the enhanced diffusion.
Claim 13
Independent Claim
169 words
The method of enhancing diffusion of selected atom species into a semiconductor substrate which comprises the steps of predepositing on at least one surface of said substrate a layer of material containing the selected atom species, elevating the temperature of the substrate to a temperature which permits interstitial lattice atoms and lattice vacancies to move freely in the substrate, said temperature being below the temperature which would produce significant diffusion of the selected atom species into the substrate, and simultaneously bombarding at said surface selected areas of the substrate with a non-dopant particle beam for the substrate so that the particles collide with atoms in the substrate to dislodge atoms from their lattice position and create lattice vacancies which move freely in the substrate at said elevated temperature to interact with said selected atom species at said elevated temperature to enhance diffusion of the selected atom species from the surface into the substrate, said temperature and particle beam being such that no gross damage is caused in the substrate.
Claim 14
Dependent Claim
44 words
The method as in claim 14 in which said substrate is semiconductive material characterizing one conductivity type and said layer contains atom species characterizing an opposite conductivity type to thereby form a region in said substrate which defines a rectifying junction in said substrate.
Claim 15
Dependent Claim
28 words
The method as in claim 14 in which said substrate is semiconductor material characterizing one conductivity type and said layer contains atom species characterizing said one conductivity type.
Claim 16
Dependent Claim
86 words
The method as in claim 14 in which said substrate is semiconductor material characterizing one conductivity type and said layer contains atom species characterizing both said one conductivity type and an opposite conductivity type, saiD atom species of opposite conductivity type having a higher diffusion coefficient than said atom species of said one conductivity type whereby said atom species of said opposite conductivity type diffuses further into said substrate than the atom species of said one conductivity type to form two rectifying junctions in said substrate.
Claim 17
Dependent Claim
18 words
The method as in claim 14 in which said layer is applied on selected areas of said surface.
Claim 18
Dependent Claim
43 words
The method as in claim 14 wherein a mask is provided over said layer, said mask containing openings in those regions which are to be diffused into said substrate and serving to inhibit penetration of said particles in said substrate in other regions.
Claim 19
Dependent Claim
19 words
The method as in claim 14 wherein said bombardment is focused and directed to selected areas of said surface.
Claim 20
Dependent Claim
52 words
The method as in claim 15 in which there is provided the additional step of applying a second layer of said one conductivity type to said substrate, elevating the temperature of the substrate, and thereafter bombarding said substrate to form a second region which forms a rectifying junction with the first region.
Claim 21
Dependent Claim
36 words
The method as in claim 15 in which there is thereafter provided a layer of said opposite conductivity type, the temperature is elevated and the surface is bombarded to form an ohmic connection to said region.
Claim 22
Dependent Claim
24 words
The method as in claim 14 in which the energy of said beam is controlled to provide diffusions at different depths in said substrate.
Claim 23
Dependent Claim
53 words
The method as in claim 14 wherein a protective coating is applied over said layer and the energy of the bombarding beam is selected to penetrate said layer into said substrate whereby to inhibit the escape of either predeposited atom species or semiconductor lattice atom species from the surface during the enhanced diffusion.
Claim 24
Dependent Claim
22 words
The method as in claim 14 wherein the predeposited layer of material contains atomic species that control carrier lifetime in said semiconductor.
Claim 25
Dependent Claim
31 words
The method as in claim 14 wherein the predeposited layer of material contains atomic species that act to compensate the doping effect provided by atomic species previously introduced into the semiconductor.
Claim 26
Independent Claim
137 words
The method of enhancing diffusion of selected atom species in a semiconductor substrate which comprises the steps of providing said selected atom species, elevating the temperature of the substrate to a temperature which permits interstitial lattice atoms and lattice vacancies to move freely in said substrate and bombarding at least one surface of said substrate while the temperature is elevated with a non-dopant beam of particles selected such that the particles collide with the atoms in the substrate to dislodge atoms from the lattice positions, said temperature selected whereby no gross damage is caused in the substrate by said particle beam, said particle beam serving to create lattice vacancies which move freely in the substrate at said elevated temperature to interact with the atom species to enhance the diffusion of said selected atom species in the substrate.
Claim 27
Dependent Claim
16 words
The method as in claim 27 wherein said selected atom species is deposited on said surface.
Claim 28
Dependent Claim
19 words
The method as in claim 27 wherein said particle beam comprises a proton beam having energies above 1 keV.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-27 | 1976-08-28 | 1977-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-27 | 1980-08-28 | 1981-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-27 | 1984-08-28 | 1985-02-27 | $7700.00 | Window Closed / Lapsed |