US4155785A
Expired / Lapsed
US
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Process of making a radiation responsive device
Assignee: International Business Machines Corp
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Filing: 1977-12-02
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Granted: 1979-05-22
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Expires: 1997-12-02
Abstract
Abstract The practice of this disclosure obtains a relatively high efficiency operation for a crystalline semiconductor solar cell containing various defects of the linear and planar types. Linear defects include screw dislocations as well as full and partial dislocations. Planar defects include twins, stacking faults, grain boundaries and surfaces. Such defects normally contain recombination centers at which electrons and holes generated in the semiconductor region recombine with loss to the external current of the charge carried thereby. Through application of the principles of this invention, especial dopant concentrations and conductivity regions are established in a finite region around the linear and planar defects so that electrons and holes which are generated in the semiconductor region by incident radiation are substantially collected for external current as consequence thereof.
Inventors
- 👤 Jerome J. Cuomo
- 👤 Thomas H. DiStefano
- 👤 Robert Rosenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:28
CPC Classifications
H; H10; H10F; H10F77/00; H10F77/10; H10F77/16; H10F77/162; H10F77/164; H10F10/00; H10F10/10; H10F10/14; H10F10/18; H10F77/1642; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/546; Y02E10/547; Y10; Y10S; Y10S148/00; Y10S148/128; Y10S438/00; Y10S438/914; Y10S438/922
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
259 words
Method for enhancing the efficiency of a crystalline semiconductor device, having a crystalline semiconductor body, with a polycrystalline semiconductor region therein with columnar grains of one conductivity type including a semiconductor junction in association therewith, and having a carrier collection surface adapted to receive said radiation, metallic contacts connected to said body for substantially collecting electrons and holes generated by incident radiation in the active volume of said semiconductor body as external current, wherein said efficiency is measured by the ratio of electrical energy out to radiation energy in, comprising the steps of: treating the linear and planar defects in said semiconductor region which are topologically connected to said carrier collection surface of said semiconductor region and which normally contribute to energy loss in said semiconductor region as result of recombination process at recombination sites thereat, including doping said semiconductor body with a dopant of opposite conductivity type preferentially and selectively in the vicinity of said linear and planar defects so as to preclude substantially recombination of generated electron-hole pairs at recombination centers in said defects by repelling charge carriers of opposite conductivity type therefrom, by two steps including diffusing said additive dopant at a relatively low temperature at which the dominant diffusion process is along the linear and planar defects and subsequently diffusing said dopant at a relatively high temperature at which lattice diffusion also is accomplished so that said additional dopant is distributed preferentially and selectively in a finite region of said semiconductor material in the vicinity of said linear and planar defects of said semiconductor region.
Claim 2
Dependent Claim
259 words
Method for enhancing the efficiency of a crystalline semiconductor device, having a crystalline semiconductor body, with a polycrystalline semiconductor region therein with columnar grains of one conductivity type including a semiconductor junction in association therewith, and having a carrier collection surface adapted to receive said radiation, metallic contacts connected to said body for substantially collecting electrons and holes generated by incident radiation in the active volume of said semiconductor body as external current, wherein said efficiency is measured by the ratio of electrical energy out to radiation energy in, comprising the steps of: treating the linear and planar defects in said semiconductor region which are topologically connected to said carrier collection surface of said semiconductor region and which normally contribute to energy loss in said semiconductor region as result of recombination process at recombination sites thereat, including doping said semiconductor body with a dopant of opposite conductivity type preferentially and selectively in the vicinity of said linear and planar defects so as to preclude substantially recombination of generated electron-hole pairs at recombination centers in said defects by repelling charge carriers of opposite conductivity type therefrom, by two steps including diffusing said additive dopant at a relatively low temperature at which the dominant diffusion process is along the linear and planar defects and subsequently diffusing said dopant at a relatively high temperature at which lattice diffusion also is accomplished so that said additional dopant is distributed preferentially and selectively in a finite region of said semiconductor material in the vicinity of said linear and planar defects of said semiconductor region.
Claim 3
Dependent Claim
29 words
Method as set forth in claim 1 wherein said semiconductor region is comprised of material from the group consisting of III-V, II-VI, and IV Groups from the periodic table.
Claim 4
Dependent Claim
35 words
Method as set forth in claim 2 wherein said semiconductor region is comprised of P-type silicon and said additional selective dopant is comprised of a dopant selected from the group consisting of arsenic and phosphorus.
Claim 5
Dependent Claim
35 words
Method as set forth in claim 2 wherein said semiconductor region is comprised of P-type GaAs and additional selective dopant is comprised of a dopant selected from the group consisting of S, Se, and Te.
Claim 6
Dependent Claim
31 words
Method as set forth in claim 1 wherein said crystalline semiconductor region is a polycrystalline material and where said planar defects are grain boundaries and where said linear defects are dislocations.
Claim 7
Dependent Claim
13 words
Method as set forth in claim 5 wherein said polycrystalline material is silicon.
Claim 8
Dependent Claim
29 words
Method as set forth in claim 6 wherein said polycrystalline silicon material is P-doped with boron and said grain boundaries and dislocation are selectively doped with phosphorus or arsenic.
Claim 9
Dependent Claim
118 words
Method of fabricating, for a solar radiation responsive device, a polycrystalline semiconductor film with columnar grains of one conductivity type with a high efficiency for conversion of radiation to current which comprises the step of: preferentially and heavily doping the region of material near the surface of each grain with a dopant material of different conductivity type than that of the substantial body of the grain in which said step for preferentially doping said regions near the grain boundaries includes diffusing, at a first low temperature, said dopant material into the grain boundaries of said film, and diffusing, at a second high temperature, said dopant material from said grain boundaries into the respective regions near said grain boundaries.
Claim 10
Dependent Claim
118 words
Method of fabricating, for a solar radiation responsive device, a polycrystalline semiconductor film with columnar grains of one conductivity type with a high efficiency for conversion of radiation to current which comprises the step of: preferentially and heavily doping the region of material near the surface of each grain with a dopant material of different conductivity type than that of the substantial body of the grain in which said step for preferentially doping said regions near the grain boundaries includes diffusing, at a first low temperature, said dopant material into the grain boundaries of said film, and diffusing, at a second high temperature, said dopant material from said grain boundaries into the respective regions near said grain boundaries.
Claim 11
Dependent Claim
68 words
Method of preferentially doping a semiconductor thin film as put forth in claim 8, in which said preferential doping of the region near the grain bouundary is accomplished by: diffusing the dopant into the film at a sufficiently low temperature that grain boundary diffusion is dominant, and diffusing said dopant material from said grain boundaries at a temperature substantially above that at which grain boundary diffusion is dominant.
Claim 12
Dependent Claim
172 words
Method of fabricating, for a radiation responsive device, a multi-grain columnar layer of semiconductor material of high efficiency for conversion of radiation to current on an insulating substrate by the steps comprising: forming the grains of said material by deposition by a procedure selected from the group consisting of chemical vapor deposition, sputtering, and vacuum evaporation, in which said material contains a low level of dopant material of one conductivity type, preferentially doping said grains near said surface of each grain by diffusing a large amount of other dopant material of opposite conductivity type into the surface of each grain where said other dopant material is of different type than said dopant material of the body of the grain including diffusing at a first low temperature diffusion said dopant material of opposite conductivity type into said surfaces of said grains including grain boundaries, and diffusing at a second high temperature said latter dopant material from said layer in which said surfaces have been doped into the regions of said film adjacent thereto.
Claim 13
Dependent Claim
172 words
Method of fabricating, for a radiation responsive device, a multi-grain columnar layer of semiconductor material of high efficiency for conversion of radiation to current on an insulating substrate by the steps comprising: forming the grains of said material by deposition by a procedure selected from the group consisting of chemical vapor deposition, sputtering, and vacuum evaporation, in which said material contains a low level of dopant material of one conductivity type, preferentially doping said grains near said surface of each grain by diffusing a large amount of other dopant material of opposite conductivity type into the surface of each grain where said other dopant material is of different type than said dopant material of the body of the grain including diffusing at a first low temperature diffusion said dopant material of opposite conductivity type into said surfaces of said grains including grain boundaries, and diffusing at a second high temperature said latter dopant material from said layer in which said surfaces have been doped into the regions of said film adjacent thereto.
Claim 14
Dependent Claim
70 words
Method of fabricating said multi-grain layer as a polycrystalline film as set forth in claim 10 in which said preferential doping of the region near the grain boundary is accomplished by: diffusing the dopant into the film at a sufficiently low temperature that grain boundary diffusion is dominant, and diffusing said dopant material from said grain boundaries at a temperature substantially above that at which grain boundary diffusion is dominant.
Claim 15
Dependent Claim
31 words
Method as set forth in claim 10 wherein said semiconductor region is comprised of a material selected from the group consisting of III-V, II-V, and IV Groups from the periodic table.
Claim 16
Dependent Claim
33 words
Method as set forth in claim 12 wherein said semiconductor region is comprised of a material selected from the class consisting of Si, Ge, CdS, CdSe, CdTe, GaAs, GaP, ZnO, InP and ZnS.
Claim 17
Dependent Claim
29 words
Method as set forth in claim 12 wherein said semiconductor region is comprised of Si and said selective dopant is selected from the class consisting of As and P.
Claim 18
Dependent Claim
223 words
In a method of fabricating a radiation responsive device having a single crystalline semiconductor region of one conductivity type, said crystalline region having defects associated therewith selected from the class consisting of linear and planar defects which are topologically connected to said carrier collection surface of said semiconductor region, having at least two independent current carrying conductors associated with said semiconductor region for communicating to load means current developed as consequence of generation of electron-hole pairs in said semiconductor region by incident radiation, and having semiconductor junction means associated with said semiconductor region for establishing an internal electric field pattern in said semiconductor region, the step of: providing conductive zones along said defects within said semiconductor region so that said internal electric field established by said semiconductor junction is preferentially altered so that recombination centers at said defects have lessened capability of effecting recombination of electrons and holes thereat, wherein said zones are provided by diffusing dopant of opposite conductivity type at low temperature at which the dominant diffusion process is along the linear and planar defects, and subsequently diffusing said dopant at relatively high temperature at which lattice diffusion also is accomplished so that said dopant is distributed preferentially and selectively in a finite region of said semiconductor material in the vicinity of said linear and planar defects of said semiconductor region.
Claim 19
Dependent Claim
223 words
In a method of fabricating a radiation responsive device having a single crystalline semiconductor region of one conductivity type, said crystalline region having defects associated therewith selected from the class consisting of linear and planar defects which are topologically connected to said carrier collection surface of said semiconductor region, having at least two independent current carrying conductors associated with said semiconductor region for communicating to load means current developed as consequence of generation of electron-hole pairs in said semiconductor region by incident radiation, and having semiconductor junction means associated with said semiconductor region for establishing an internal electric field pattern in said semiconductor region, the step of: providing conductive zones along said defects within said semiconductor region so that said internal electric field established by said semiconductor junction is preferentially altered so that recombination centers at said defects have lessened capability of effecting recombination of electrons and holes thereat, wherein said zones are provided by diffusing dopant of opposite conductivity type at low temperature at which the dominant diffusion process is along the linear and planar defects, and subsequently diffusing said dopant at relatively high temperature at which lattice diffusion also is accomplished so that said dopant is distributed preferentially and selectively in a finite region of said semiconductor material in the vicinity of said linear and planar defects of said semiconductor region.
Claim 20
Dependent Claim
19 words
Method as set forth in claim 15 wherein the single crystalline region is cut from a bulk single crystal.
Claim 21
Dependent Claim
26 words
Method as set forth in claim 16 wherein said linear and planar defects in said single crystalline region are produced by said cutting by a saw.
Claim 22
Dependent Claim
21 words
Method as set forth in claim 15 where said single crystalline region is cut from crystalline ribbons of flat grown crystals.
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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) | 1982-05-21 | 1982-11-20 | 1983-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-21 | 1986-11-20 | 1987-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-21 | 1990-11-20 | 1991-05-22 | $7700.00 | Window Closed / Lapsed |