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US6025585A
Expired / Lapsed
US
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Low-resistivity photon-transparent window attached to photo-sensitive silicon detector
Assignee: University of California
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Filing: 1997-10-31
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Granted: 2000-02-15
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Expires: 2017-10-31
Abstract
Abstract The invention comprises a combination of a low resistivity, or electrically conducting, silicon layer that is transparent to long or short wavelength photons and is attached to the backside of a photon-sensitive layer of silicon, such as a silicon wafer or chip. The window is applied to photon sensitive silicon devices such as photodiodes, charge-coupled devices, active pixel sensors, low-energy x-ray sensors and other radiation detectors. The silicon window is applied to the back side of a photosensitive silicon wafer or chip so that photons can illuminate the device from the backside without interference from the circuit printed on the frontside. A voltage sufficient to fully deplete the high-resistivity photosensitive silicon volume of charge carriers is applied between the low-resistivity back window and the front, patterned, side of the device. This allows photon-induced charge created at the backside to reach the front side of the device and to be processed by any circuitry attached to the front side. Using the inventive combination, the photon sensitive silicon layer does not need to be thinned beyond standard fabrication methods in order to achieve full charge-depletion in the silicon volume. In one embodiment, the inventive backside window is applied to high resistivity silicon to allow backside illumination while maintaining charge isolation in CCD pixels.
Inventors
- 👤 Stephen Edward Holland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:05
CPC Classifications
H; H10; H10F; H10F39/00; H10F39/80; H10F39/807; H10F39/011; H10F39/024; H10F39/10; H10F39/12; H10F39/15; H10F39/151; H10F39/199; H10F39/805; H10F77/00; H10F77/20; H10F77/244; H10F77/247; H10F77/30; H10F77/306
Claims Analysis
Total Claims: 46
Claim 1
Independent Claim
32 words
A back-illuminated photon sensing element comprising, a) a photon-sensitive silicon substrate having a frontside and a backside; and b) an electrically-conducting photon-transparent silicon layer attached to the backside of the photon-sensitive substrate.
Claim 2
Dependent Claim
32 words
A back-illuminated photon sensing element comprising, a) a photon-sensitive silicon substrate having a frontside and a backside; and b) an electrically-conducting photon-transparent silicon layer attached to the backside of the photon-sensitive substrate.
Claim 3
Dependent Claim
22 words
The photon sensing element of claim 1 wherein the photon-sensitive silicon substrate is between about 20 μm and about 5000 μm thick.
Claim 4
Dependent Claim
22 words
The photon sensing element of claim 1 wherein the photon-sensitive silicon substrate is between about 40 μm and about 4000 μm thick.
Claim 5
Dependent Claim
22 words
The photon sensing element of claim 1 wherein the photon-sensitive silicon substrate is between about 50 μm and about 2000 μm thick.
Claim 6
Dependent Claim
22 words
The photon sensing element of claim 1 wherein the photon-sensitive silicon substrate is between about 75 μm and about 1000 μm thick.
Claim 7
Dependent Claim
22 words
The photon sensing element of claim 1 wherein the photon-sensitive silicon substrate is between about 100 μm and about 750 μm thick.
Claim 8
Dependent Claim
22 words
The photon sensing element of claim 1 wherein the photon-sensitive silicon substrate is between about 100 μm and about 625 μm thick.
Claim 9
Dependent Claim
22 words
The photon sensing element of claim 1 wherein the photon-sensitive silicon substrate is between about 200 μm and about 625 μm thick.
Claim 10
Dependent Claim
22 words
The photon sensing element of claim 1 wherein the photon-sensitive silicon substrate is between about 250 μm and about 625 μm thick.
Claim 11
Dependent Claim
22 words
The photon sensing element of claim 1 wherein the photon-sensitive silicon substrate is between about 300 μm and about 550 μm thick.
Claim 12
Dependent Claim
23 words
The photon sensing element of claim 1 wherein the photon-sensitive silicon substrate resistivity, ρ, is between about 3 KΩ-cm and about 20 kΩ-cm.
Claim 13
Dependent Claim
23 words
The photon sensing element of claim 1 wherein the photon-sensitive silicon substrate resistivity, ρ, is between about 100 Ω-cm and about 20 kΩ-cm.
Claim 14
Dependent Claim
23 words
The photon sensing element of claim 1 wherein the photon-sensitive silicon substrate resistivity, ρ, is between about 1 KΩ-cm and about 20 kΩ-cm.
Claim 15
Dependent Claim
23 words
The photon sensing element of claim 1 wherein the photon-sensitive silicon substrate resistivity, ρ, is between about 10.5 KΩ-cm and about 20 kΩ-cm.
Claim 16
Dependent Claim
14 words
The photon sensing element of claim 12 wherein the photon-sensitive substrate comprises n-type silicon.
Claim 17
Dependent Claim
14 words
The photon sensing element of claim 12 wherein the photon-sensitive substrate comprises p-type silicon.
Claim 18
Dependent Claim
21 words
The photon sensing element of claim 1 wherein the backside layer is between about 10 nm and about 100 μm thick.
Claim 19
Dependent Claim
21 words
The photon sensing element of claim 1 wherein the backside layer is between about 10 nm and about 10 μm thick.
Claim 20
Dependent Claim
21 words
The photon sensing element of claim 1 wherein the backside layer is between about 10 nm and about 1 μm thick.
Claim 21
Dependent Claim
21 words
The photon sensing element of claim 1 wherein the backside layer is between about 10 nm and about 100 nm thick.
Claim 22
Dependent Claim
21 words
The photon sensing element of claim 1 wherein the backside layer is between about 10 nm and about 50 nm thick.
Claim 23
Dependent Claim
24 words
The photon sensing element of claim 1 wherein the backside layer is doped to between about 0.0001 and about 10 atomic percent with phosphorous.
Claim 24
Dependent Claim
24 words
The photon sensing element of claim 1 wherein the backside layer is doped to between about 0.001 and about 3 atomic percent with phosphorous.
Claim 25
Dependent Claim
24 words
The photon sensing element of claim 1 wherein the backside layer is doped to between about 0.1 and about 3 atomic percent with phosphorous.
Claim 26
Dependent Claim
44 words
The photon sensing element of claim 1 further comprising an antireflecting coating on the backside of the backside layer, chosen from the group consisting of transparent conducting oxides, indium tin oxide, silicon dioxide, silicon nitride, magnesium fluoride, hafnium oxide, lead oxide, and aluminum oxide.
Claim 27
Dependent Claim
22 words
The photon sensing element of claim 25 wherein the antireflecting layer is from the group of materials known as transparent conducting oxides.
Claim 28
Dependent Claim
15 words
The photon sensing element of claim 26 wherein the antireflecting layer is indium tin oxide.
Claim 29
Dependent Claim
45 words
An electromagnetic radiation detector comprising, a) a photon-sensitive high-resistivity silicon substrate having a frontside and a backside; b) a layer of electrically conducting silicon attached to the backside of the photon-sensitive substrate; and c) a charge collecting region on the frontside of the photon-sensitive substrate.
Claim 30
Dependent Claim
45 words
An electromagnetic radiation detector comprising, a) a photon-sensitive high-resistivity silicon substrate having a frontside and a backside; b) a layer of electrically conducting silicon attached to the backside of the photon-sensitive substrate; and c) a charge collecting region on the frontside of the photon-sensitive substrate.
Claim 31
Dependent Claim
19 words
The detector of claim 28 wherein the photon-sensitive substrate is between about 200 μm and about 750 μm thick.
Claim 32
Dependent Claim
28 words
The detector of claim 29 wherein the backside layer has a thickness that is transparent to photons having a wavelength between about 400 nm and about 1100 nm.
Claim 33
Dependent Claim
15 words
The detector of claim 30 further comprising an antireflective coating applied to the backside layer.
Claim 34
Dependent Claim
12 words
The detector of claim 31 wherein the antireflective coating is electrically conducting.
Claim 35
Dependent Claim
15 words
The detector of claim 28 further comprising a voltage source connected to the backside layer.
Claim 36
Dependent Claim
45 words
The electromagnetic radiation detector of claim 28 having an array of pixels comprising, a) a doped charge collecting region; b) an oppositely doped stop region; and c) a region of high resistivity silicon between and adjacent to the charge collecting region and the stop region.
Claim 37
Dependent Claim
69 words
A back-illuminated photodiode comprising a) a photon-sensitive silicon substrate having a frontside and a backside; b) a layer of electrically conducting polycrystalline silicon attached to the backside of the photon-sensitive substrate, said layer having a thickness that is transparent to the photons being detected; c) a charge collecting region on the frontside of the photon-sensitive substrate; and d) an electrical connection for a voltage source on the backside layer.
Claim 38
Dependent Claim
69 words
A back-illuminated photodiode comprising a) a photon-sensitive silicon substrate having a frontside and a backside; b) a layer of electrically conducting polycrystalline silicon attached to the backside of the photon-sensitive substrate, said layer having a thickness that is transparent to the photons being detected; c) a charge collecting region on the frontside of the photon-sensitive substrate; and d) an electrical connection for a voltage source on the backside layer.
Claim 39
Dependent Claim
77 words
A back-illuminated charge coupled device comprising, a) a high-resistivity photon-sensitive silicon substrate having a thickness between about 200 μm and about 1 mm and having a frontside and a backside; b) charge coupled circuitry patterned on the frontside; c) a layer of electrically-conducting polycrystalline silicon having a thickness between about 10 nm and about 1 μm attached to the backside of the photon-sensitive substrate; and d) an electrical connection for a voltage source on the backside layer.
Claim 40
Dependent Claim
77 words
A back-illuminated charge coupled device comprising, a) a high-resistivity photon-sensitive silicon substrate having a thickness between about 200 μm and about 1 mm and having a frontside and a backside; b) charge coupled circuitry patterned on the frontside; c) a layer of electrically-conducting polycrystalline silicon having a thickness between about 10 nm and about 1 μm attached to the backside of the photon-sensitive substrate; and d) an electrical connection for a voltage source on the backside layer.
Claim 41
Dependent Claim
23 words
The charged couple device of claim 36 wherein the photon-sensitive silicon substrate has a resistivity between about 1 KΩ-cm and about 20 kΩ-cm.
Claim 42
Dependent Claim
17 words
The charged couple device of claim 36 further comprising an antireflective coating applied to the backside layer.
Claim 43
Dependent Claim
17 words
The charged couple device of claim 36 further comprising a voltage source connected to the electrical connection.
Claim 44
Dependent Claim
77 words
A back-illuminated charge coupled device comprising, a) a low-resistivity photon-sensitive silicon substrate having a thickness between about 20 μm and about 50 μm and having a frontside and a backside; b) charge coupled circuitry patterned on the frontside; c) a layer of electrically-conducting polycrystalline silicon having a thickness between about 10 nm and about 1 μm attached to the backside of the photon-sensitive substrate; and d) an electrical connection for a voltage source on the backside layer.
Claim 45
Dependent Claim
77 words
A back-illuminated charge coupled device comprising, a) a low-resistivity photon-sensitive silicon substrate having a thickness between about 20 μm and about 50 μm and having a frontside and a backside; b) charge coupled circuitry patterned on the frontside; c) a layer of electrically-conducting polycrystalline silicon having a thickness between about 10 nm and about 1 μm attached to the backside of the photon-sensitive substrate; and d) an electrical connection for a voltage source on the backside layer.
Claim 46
Dependent Claim
23 words
The charged couple device of claim 40 wherein the photon-sensitive silicon substrate has a resistivity between about 1 Ω-cm and about 100 Ω-cm.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2003-02-14 | 2003-08-16 | 2004-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-02-14 | 2007-08-16 | 2008-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-02-14 | 2011-08-16 | 2012-02-15 | $7700.00 | Window Closed / Lapsed |