US3908183A
Expired / Lapsed
US
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Combined ion implantation and kinetic transport deposition process
Assignee: California Linear Circuits Inc
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Filing: 1973-03-14
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Granted: 1975-09-23
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Expires: 1993-03-14
Abstract
Abstract Combined low energy, high density ion implantation and kinetic transport deposition of refractory or other materials is carried out under very high vacuum conditions. The process facilitates formation of large area, highly doped, shallow semiconductor junctions and the associated electrodes. The steps of preimplantation cleaning, ion implantation for junction formation, ohmic contact formation by kinetic transport deposition, and postimplantation anneal all are carried out in the same chamber. Under high vacuum, pre-implantation cleaning and annealing of semi-conductor substrates is accomplished by electron bombardment and concomitant heating from an annular flood filament. Next a conical electron beam vaporizes solid source material within the evacuated chamber, ionizing some of the vaporized particles. The result is a plasma expansion source including ions which are accelerated electrostatically for implantation in the target, and atoms which are kinetically transported toward the target to form an ohmic contact or other metalization layer. Additional build-up of kinetically transported material occurs after ion implantation is complete. Post-implantation annealing is carried out using electron bombardment to heat the targets to above an annealing threshhold for a period of time short enough so that no undesirable diffusion occurs. The substrates then are rapidly forced cooled. Repeating the process using another source permits different refractory materials to be layered. The combined kinetic transport deposition and ionimplantation into the underlying stratum effectively bonds the second material to the previously deposited layer.
Inventors
- 👤 Jr Robert M Ennis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:15
CPC Classifications
H; H10; H10P; H10P30/00; H10P30/20; H01; H01J; H01J37/00; H01J37/30; H01J37/317; H01J37/3171; H10P95/00; H10P95/90; Y; Y10; Y10S; Y10S148/00; Y10S148/02; Y10S148/045; Y10S148/169; Y10S438/00; Y10S438/913
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
97 words
A COMBINED ION IMPLANTATION AND KINETIC TRANSPORT DEPOSITION PROCESS COMPRISING: VAPORIZING A SOLID SOURCE MATERIAL WITHIN A CHAMBER UNDER HIGH VACUUM USING AN ELECTRON BEAM DIRECTED TOWARD SAID SOLID SOURCE MATERIAL, SAID BEAM ALSO IONISING A PORTION OF THE VAPORIZED PARTICLES OF SOURCE MATERIAL, THEREBY FORMING AN EXPANDING PLASMA, IMPLANTING IONS FROM SAID PLASMA INTO A TARGET BY ELECTROSTATICALLY ACCELERATING SAID IONS TOWARD SAID TARGET FOR IMPLANTATION THEREIN IN THE ABSENCE OF AN EXTERNAL MAGNETIC FIELD, WHILE PERMITTING KINETICALLY TRANSPORTED ATOMS FROM SAID PLASMA TO DEPOSIT AS A LAYER ATOP THE ION IMPLANTED REGION OF SAID TARGET.
Claim 2
Dependent Claim
97 words
A COMBINED ION IMPLANTATION AND KINETIC TRANSPORT DEPOSITION PROCESS COMPRISING: VAPORIZING A SOLID SOURCE MATERIAL WITHIN A CHAMBER UNDER HIGH VACUUM USING AN ELECTRON BEAM DIRECTED TOWARD SAID SOLID SOURCE MATERIAL, SAID BEAM ALSO IONISING A PORTION OF THE VAPORIZED PARTICLES OF SOURCE MATERIAL, THEREBY FORMING AN EXPANDING PLASMA, IMPLANTING IONS FROM SAID PLASMA INTO A TARGET BY ELECTROSTATICALLY ACCELERATING SAID IONS TOWARD SAID TARGET FOR IMPLANTATION THEREIN IN THE ABSENCE OF AN EXTERNAL MAGNETIC FIELD, WHILE PERMITTING KINETICALLY TRANSPORTED ATOMS FROM SAID PLASMA TO DEPOSIT AS A LAYER ATOP THE ION IMPLANTED REGION OF SAID TARGET.
Claim 3
Dependent Claim
27 words
A process according to claim 1 wherein said electrostatic acceleration is terminated prior to termination of said kinetic transport, thereby increasing the thickness of said deposited layer.
Claim 4
Dependent Claim
31 words
A process according to claim 1 wherein said target comprises a semiconductor substrate, said implanted ions forming a junction in said substrate, said deposited atoms forming an electrode for said junction.
Claim 5
Dependent Claim
17 words
A process according to claim 3 further comprising: annealing said substrate within said chamber employing electron bombardment.
Claim 6
Dependent Claim
70 words
A process according to claim 4 wherein said annealing is carried out subsequent to said ion implantation and kinetic transport deposition, said electron bombardment heating said substrate to above an annealing threshhold temperature of said semiconductor for a time duration sufficient to anneal lattice damage and to transfer implanted ions from interstitial to substitutional positions, but short enough to prevent diffusion of implanted ions, said substrate then being rapidly cooled.
Claim 7
Dependent Claim
23 words
A process according to claim 5 wherein the temperature of said substrate is maintained below said semi-conductor annealing threshhold during said ion implantation.
Claim 8
Dependent Claim
30 words
A process according to claim 3 further comprising: heating said substrate by electron bombardment, prior to ion implantation, to a temperature sufficient to desorb fluids or gases from said substrate.
Claim 9
Dependent Claim
30 words
A process according to claim 1 wherein said electron beam is conical and focused on said source material, the energy of said beam being sufficient to vaporize solid refractory material.
Claim 10
Dependent Claim
44 words
A process according to claim 1 followed by like ion implantation and kinetic transport deposition of a different vaporized source material, ions of said different material being implanted into the previously deposited layer to bond the kinetically transported different material to said previous layer.
Claim 11
Dependent Claim
46 words
A process according to claim 2 wherein said ion implantation is carried out shortly after vaporization of said source material begins, the vaporization rate then being relatively low, and wherein kinetic transport deposition is continued at a later time after the vaporization rate has increased substantially.
Claim 12
Dependent Claim
38 words
A process according to claim 3 wherein the ion acceleration potential is below about 10 keV and wherein the ion current density is above about 1 ma/cm2, thereby facilitating formation of shallow junctions having high implanted ion concentration.
Claim 13
Dependent Claim
100 words
A PROCESS FOR THE FORMATION OF A SEMICONDUCTOR DEVICE INCLUDING A SHALLOW JUNCTION AND AN OHMIC CONTACT THEREFOR, COMPRISING: PLACING A SEMICONDUCTOR WAFER IN A CHAMBER, EVACUATING SAID CHAMBER TO A HIGH VACUUM, USING AN ELECTRON BEAM TO VAPORIZE SOURCE MATERIAL WITHIN SAID EVACUATED CHAMBER, SAID BEAM IONIZING SOME OF THE VAPORIZED MATERIAL, AND ELECTROSTATICALLY ACCELERATING SAID IONIZED MATERIAL TOWARD SAID WAFER WITH SUFFICIENT ENERGY TO IMPLANT SAID IONS INTO A SHALLOW REGION OF SAID WAFER, NON-IONIZED VAPORIZED PARTICLES OF SOURCE MATERIAL BEING DEPOSITED ATOP THE SURFACE OF SAID WAFER REGION CONCURRENT WITH SAID ION IMPLATATION TO BEGIN CONTACT FORMATION.
Claim 14
Dependent Claim
100 words
A PROCESS FOR THE FORMATION OF A SEMICONDUCTOR DEVICE INCLUDING A SHALLOW JUNCTION AND AN OHMIC CONTACT THEREFOR, COMPRISING: PLACING A SEMICONDUCTOR WAFER IN A CHAMBER, EVACUATING SAID CHAMBER TO A HIGH VACUUM, USING AN ELECTRON BEAM TO VAPORIZE SOURCE MATERIAL WITHIN SAID EVACUATED CHAMBER, SAID BEAM IONIZING SOME OF THE VAPORIZED MATERIAL, AND ELECTROSTATICALLY ACCELERATING SAID IONIZED MATERIAL TOWARD SAID WAFER WITH SUFFICIENT ENERGY TO IMPLANT SAID IONS INTO A SHALLOW REGION OF SAID WAFER, NON-IONIZED VAPORIZED PARTICLES OF SOURCE MATERIAL BEING DEPOSITED ATOP THE SURFACE OF SAID WAFER REGION CONCURRENT WITH SAID ION IMPLATATION TO BEGIN CONTACT FORMATION.
Claim 15
Dependent Claim
37 words
A process according to claim 12 comprising the further step of: continuing the deposition of said non-ionized particles of source material subsequent to completion of ion implantation to allow build-up of said contact to a substantial thickness.
Claim 16
Dependent Claim
14 words
A process according to claim 12 wherein said source material comprises a refractory metal.
Claim 17
Dependent Claim
40 words
A process according to claim 14 wherein the energy of said electron beam is sufficient to vaporize said refractory material, and wherein said non-ionized particles are kinetically transported toward said wafer with energies imparted upon vaporization by said electron beam.
Claim 18
Dependent Claim
27 words
A process according to claim 13 wherein further comprising: selectively blocking the transport path of said vaporized material to said wafer to control the duration of deposition.
Claim 19
Dependent Claim
57 words
A process according to claim 16 wherein said path is blocked for a period of time between completion of ion implantation and the continued kinetic transport deposition for contact thickness build-up, the vaporization rate increasing substantially during the time said path is blocked so that a high deposition rate is achieved when said path again is opened.
Claim 20
Dependent Claim
94 words
A process according to claim 13 wherein said wafers are situated in a target area near one end of said chamber, wherein said source material is situated near the other end of said chamber at the apex of a conical electron beam produced by an annular electron gun assembly mounted generally coaxially with the common axis of said source material and the center of said target area, and wherein an electrostatic ion acceleration field is produced from a cylindrical screen surrounding a portion of the ion trajectory between said source and said target area.
Claim 21
Dependent Claim
39 words
A process according to claim 12 preceeded by the step of; pre-implantation cleaning said semiconductor wafer in said chamber under high vacuum, said cleaning comprising heating said wafer by electron bombardment to a temperature in excess of about 100*C.
Claim 22
Dependent Claim
24 words
A process according to claim 13 followed by the step of; electron bombardment annealing said semiconductor wafer in said same chamber under high vacuum.
Claim 23
Dependent Claim
69 words
A process according to claim 20 wherein said wafers are mounted on a target holder within said chamber, said electron bombardment annealing comprising flooding said wafers with electrons from an annular flood filament mounted within said chamber surrounding the transport path to said wafers, said electron bombardment raising the temperature of said wafers to above an annealing threshold said wafers then being force cooled to below said threshold temperature.
Claim 24
Dependent Claim
35 words
A process according to claim 12 followed by like ion implantation and concurrent kinetic transport deposition of a vaporized different source material to form a layer of said different material atop the previously formed contact.
Claim 25
Dependent Claim
11 words
A semiconductor device formed according to the process of claim 12.
Claim 26
Dependent Claim
93 words
A PROCESS FOR DEPOSITING A LAYER OF A SECOND MATERIAL ONTO A STRATUM OF A FIRST MATERIAL, COMPRISING: PLACING A TARGET INCLUDING SAID STRATUM INTO A CHAMBER AND EVACUATING SAID CHAMBER, PRODUCING IN SAID EVACUATED CHAMBER AN EXPANDING PLASMA SOURCE INCLUDING BOTH IONS AND NON-IONIZED ATOMS OF SAID SECOND MATERIAL, ELECTROSTICALLY ACCELERATING IONS FROM SAID PLASMA TOWARD SAID TARGET FOR IMPLANTATION INTO SAID STRATUM, AND CONCURRENTLY PERMITTING KINETIC TRANSPORT OF SAID NON-IONIZED ATOMS FROM SAID PLASMA TOWARD SAID TARGET TO BEING DEPOSITION OF SAID LAYER ABOVE THE ION IMPLANTED PORTION OF SAID STRATUM.
Claim 27
Dependent Claim
93 words
A PROCESS FOR DEPOSITING A LAYER OF A SECOND MATERIAL ONTO A STRATUM OF A FIRST MATERIAL, COMPRISING: PLACING A TARGET INCLUDING SAID STRATUM INTO A CHAMBER AND EVACUATING SAID CHAMBER, PRODUCING IN SAID EVACUATED CHAMBER AN EXPANDING PLASMA SOURCE INCLUDING BOTH IONS AND NON-IONIZED ATOMS OF SAID SECOND MATERIAL, ELECTROSTICALLY ACCELERATING IONS FROM SAID PLASMA TOWARD SAID TARGET FOR IMPLANTATION INTO SAID STRATUM, AND CONCURRENTLY PERMITTING KINETIC TRANSPORT OF SAID NON-IONIZED ATOMS FROM SAID PLASMA TOWARD SAID TARGET TO BEING DEPOSITION OF SAID LAYER ABOVE THE ION IMPLANTED PORTION OF SAID STRATUM.
Claim 28
Dependent Claim
39 words
A process according to claim 24 wherein said stratum comprises non-semiconductive material, and wherein said ion implantation is to a depth less than the thickness of said stratum, said implantation aiding to bond said deposited layer to said stratum.
Claim 29
Dependent Claim
16 words
A process according to claim 25 wherein said first and second materials are different refractory metals.
Claim 30
Dependent Claim
33 words
A process according to claim 24 wherein said first material is a semiconductor, said implantation changing the conductivity characteristics of a region of said semiconductor, said layer comprising an electrode for said region.
Claim 31
Dependent Claim
45 words
A process according to claim 24 wherein said expanding plasma is produced by using a high energy conical electron beam to vaporize a solid source of said second material within said evacuated chamber, the pressure in said chamber being sufficiently low to maintain said plasma.
Claim 32
Dependent Claim
26 words
A process according to claim 25 further comprising: continuing said kinetic transport deposition after termination of said ion implantation to increase the thickness of said layer.
Claim 33
Dependent Claim
54 words
A process according to claim 29 wherein said ion implantation is carried out while the vaporization rate is relatively low and wherein said continued kinetic transport is carried out later when the vaporization rate has increased significantly, kinetic transport being blocked for a period of time between said concurrent transport and said continued transport.
Claim 34
Dependent Claim
28 words
A process according to claim 26 and wherein said second material comprises nickel, said process then being repeated to form an aluminum layer atop the deposited nickel layer.
Claim 35
Dependent Claim
161 words
A combined ion implantation and kinetic transport deposition process comprising: mounting a target within a chamber, evacuating said chamber to between 10 7 and 10 9 Torr, using an annular electron gun assembly within said evacuated chamber to vaporize a solid source material contained in a crucible situated at the apex of a conical electron beam produced by said assembly, said beam also ionizing some of the vaporized source material, an expanding plasma thereby being produced in the region above said crucible, producing an electrostatic field within said chamber to accelerate ions from said plasma toward said target wafer for implantation therein, flooding said target wafer with electrons from an annular filament situated within said chamber to neutralize the charge of said accelerated ions, permitting non-ionized particles from said plasma to be transported kinetically to said target wafers, and terminating said ion implantation but subsequently permitting additional kinetic transport deposition to increase the thickness of the layer resultant from such deposition.
Claim 36
Dependent Claim
161 words
A combined ion implantation and kinetic transport deposition process comprising: mounting a target within a chamber, evacuating said chamber to between 10 7 and 10 9 Torr, using an annular electron gun assembly within said evacuated chamber to vaporize a solid source material contained in a crucible situated at the apex of a conical electron beam produced by said assembly, said beam also ionizing some of the vaporized source material, an expanding plasma thereby being produced in the region above said crucible, producing an electrostatic field within said chamber to accelerate ions from said plasma toward said target wafer for implantation therein, flooding said target wafer with electrons from an annular filament situated within said chamber to neutralize the charge of said accelerated ions, permitting non-ionized particles from said plasma to be transported kinetically to said target wafers, and terminating said ion implantation but subsequently permitting additional kinetic transport deposition to increase the thickness of the layer resultant from such deposition.
Claim 37
Dependent Claim
41 words
A process according to claim 32 wherein said electrostatic field has a potential of less than about 10 keV and wherein said conical electron beam has an energy of less than about 5 keV but great enough to vaporize refractory materials.
Claim 38
Dependent Claim
36 words
A process according to claim 32 wherein said target wafer is a semiconductor, said semiconductor being heated to above about 100*C. by electron bombardment from said annular filament prior to ion implantation to desorb contaminants therefrom.
Claim 39
Dependent Claim
47 words
A process according to claim 32 wherein said target wafer is a semiconductor, said semiconductor being annealed subsequent to ion implantation by electron bombardment from said annular filament, said semiconductor wafer thereafter being force cooled by a liquid circulated through a coolant tube on said wafer mount.
Claim 40
Dependent Claim
119 words
A process for pre-depping a semiconductor device, comprising: placing a semiconductor substrate in a chamber, evacuating said chamber to a high vacuum, using an electron beam to vaporize source material within said evacuated chamber, said beam ionizing some of the vaporized material, electrostatically accelerating said ionized material toward said substrate with an acceleration energy of up to about 60 keV to implant a high concentration of said ions into a surface-adjacent region of said substrate, non-ionized vaporized particles of source material being deposited atop the surface of said substrate region concurrent with said ion implantation, and heating said substrate to a temperature sufficient to diffuse said implanted ions in said substrate to provide a diffused region of uniform concentration.
Claim 41
Dependent Claim
119 words
A process for pre-depping a semiconductor device, comprising: placing a semiconductor substrate in a chamber, evacuating said chamber to a high vacuum, using an electron beam to vaporize source material within said evacuated chamber, said beam ionizing some of the vaporized material, electrostatically accelerating said ionized material toward said substrate with an acceleration energy of up to about 60 keV to implant a high concentration of said ions into a surface-adjacent region of said substrate, non-ionized vaporized particles of source material being deposited atop the surface of said substrate region concurrent with said ion implantation, and heating said substrate to a temperature sufficient to diffuse said implanted ions in said substrate to provide a diffused region of uniform concentration.
Claim 42
Dependent Claim
42 words
A process according to claim 36 comprising the preliminary step of: cleaning said substrate by electron bombardment in said evacuated chamber prior to said ion implantation, and wherein said heating to cause diffusion also is carried out in said high vacuum chamber.
Claim 43
Dependent Claim
40 words
A process according to claim 36 comprising the additional step of depositing additional vaporized source material by kinetic transport onto the surface of said substrate subsequent to said ion implantation, said material being diffused into said substrate by said heating.
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) | 1978-09-22 | 1979-03-24 | 1979-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-22 | 1983-03-24 | 1983-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-22 | 1987-03-24 | 1987-09-23 | $7700.00 | Window Closed / Lapsed |