US4926231A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrated pin photo-detector
Assignee: Motorola Solutions Inc
•
Filing: 1988-12-28
•
Granted: 1990-05-15
•
Expires: 2008-12-28
Abstract
Abstract An improved means and method for forming an optical sensor within an integrated circuit structure is described. An epi-coated semiconductor wafer is masked and a cavity etched through the epi-layer to the underlying substrate. A dielectric sidewall is formed on the cavity sidewall and a substantially intrinsic semiconductor region, preferably grown by selective epitaxy, to refill the cavity. The upper surface of the intrinsic region is then heavily doped and contacted by a low resistance polysilicon layer which is substantially transparent to incoming light. The method forms a high sensitivity PIN photo-sensor having a thick space-charge region for efficient capture of the hole-electron pairs produced by the incoming light. The fabrication techniques are compatible with the processing requirements for other integrated circuit devices formed on the same chip and to which the PIN device is coupled without wire bonds, tabs, bumps or the like.
Inventors
- 👤 Bor-Yuan Hwang
- 👤 Carroll M. Casteel
- 👤 Sal T. Mastroianni
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:59
CPC Classifications
H; H10; H10F; H10F39/00; H10F39/10; H10F39/103
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
77 words
A light sensing device comprising: a substrate having a surface region of a first conductivity type, and having thereon an epi-layer of a second conductivity type, wherein the epi-layer comprises other integrated devices; a dielectric isolation wall extending through the epi-layer and through a portion of the substrate and providing a space separated from the epi-layer by the isolation walls; and an intrinsic semiconductor region in the space and electrically contacting the surface region of the substrate.
Claim 2
Dependent Claim
77 words
A light sensing device comprising: a substrate having a surface region of a first conductivity type, and having thereon an epi-layer of a second conductivity type, wherein the epi-layer comprises other integrated devices; a dielectric isolation wall extending through the epi-layer and through a portion of the substrate and providing a space separated from the epi-layer by the isolation walls; and an intrinsic semiconductor region in the space and electrically contacting the surface region of the substrate.
Claim 3
Dependent Claim
40 words
The light sensing device of claim 1 further comprising a doped semiconductor region of the second type electrically contacting an outward facing surface of the intrinsic region and spaced apart from the epi-layer by a portion of the isolation wall.
Claim 4
Dependent Claim
48 words
The light sensing device of claim 1 further comprising a doped semiconductor region of the first type in the surface region of the substrate electrically contacting the intrinsic region, more highly doped than the substrate, and spaced apart from the epi-layer by a portion of the isolation wall.
Claim 5
Dependent Claim
151 words
An integrated PIN diode comprising: a semiconductor substrate of a first conductivity type and having a first surface; a first semiconductor region of a second conductivity type opposite the first type on the first surface and having a second surface spaced apart from the first surface by a first distance; a lateral dielectric isolation wall extending from the second surface through the first semiconductor region to the substrate; a substantially intrinsic semiconductor region separated from the first semiconductor region by the dielectric isolation wall, contacting the substrate, and having a third surface spaced from the substrate, wherein the third surface is spaced from the substrate by a second distance and the second distance exceeds the first distance; a second semiconductor region of the second type in the intrinsic region and extending to the third surface; and an ohmic contact to the second semiconductor region permitting light to reach the intrinsic region.
Claim 6
Dependent Claim
151 words
An integrated PIN diode comprising: a semiconductor substrate of a first conductivity type and having a first surface; a first semiconductor region of a second conductivity type opposite the first type on the first surface and having a second surface spaced apart from the first surface by a first distance; a lateral dielectric isolation wall extending from the second surface through the first semiconductor region to the substrate; a substantially intrinsic semiconductor region separated from the first semiconductor region by the dielectric isolation wall, contacting the substrate, and having a third surface spaced from the substrate, wherein the third surface is spaced from the substrate by a second distance and the second distance exceeds the first distance; a second semiconductor region of the second type in the intrinsic region and extending to the third surface; and an ohmic contact to the second semiconductor region permitting light to reach the intrinsic region.
Claim 7
Dependent Claim
36 words
The diode of claim 4 further comprising a third semiconductor region of the first type and a higher conductivity than the semiconductor substrate in the first surface, in contact with and underlying the intrinsic semiconductor region.
Claim 8
Dependent Claim
25 words
The diode of claim 4 wherein the ohmic contact is formed from a layer that is substantially transparent to light absorbed in the intrinsic region.
Claim 9
Dependent Claim
16 words
The diode of claim 4 wherein the ohmic contact is formed by a polycrystalline semiconductor material.
Claim 10
Dependent Claim
19 words
The diode of claim 7 wherein the polycrystalline semiconductor material is doped with a dopant of the second type.
Claim 11
Dependent Claim
15 words
The diode of claim 4 wherein the second semiconductor region is adjacent the third surface.
Claim 12
Dependent Claim
21 words
The diode of claim 9 wherein the second semiconductor region has a thickness that is small compared to the third distance.
Claim 13
Dependent Claim
127 words
A light sensing device integrated in a monolithic integrated circuit, comprising: a substrate of a first conductivity type; an epitaxial layer of a first thickness and a second conductivity type on the substrate, containing device regions of the integrated circuit, and having a first exterior surface; a dielectric isolation wall extending through the epitaxial layer from the first exterior surface at least to the substrate; an intrinsic semiconductor region electrically contacting the substrate and laterally separated from the device regions of the integrated circuit by the isolation wall, and having a second exterior surface, wherein the intrinsic region has a second thickness greater than the first thickness; and a first doped semiconductor region of the second type electrically contacting the intrinsic region at the second exterior surface.
Claim 14
Dependent Claim
127 words
A light sensing device integrated in a monolithic integrated circuit, comprising: a substrate of a first conductivity type; an epitaxial layer of a first thickness and a second conductivity type on the substrate, containing device regions of the integrated circuit, and having a first exterior surface; a dielectric isolation wall extending through the epitaxial layer from the first exterior surface at least to the substrate; an intrinsic semiconductor region electrically contacting the substrate and laterally separated from the device regions of the integrated circuit by the isolation wall, and having a second exterior surface, wherein the intrinsic region has a second thickness greater than the first thickness; and a first doped semiconductor region of the second type electrically contacting the intrinsic region at the second exterior surface.
Claim 15
Dependent Claim
33 words
The light sensing device of claim 11 further comprising a second doped semiconductor region of the first type electrically contacting the intrinsic region adjacent the substrate and more heavily doped than the substrate.
Claim 16
Dependent Claim
17 words
The light sensing device of claim 11 further comprising an ohmic contact to the first semiconductor region.
Claim 17
Dependent Claim
21 words
The light sensing device of claim 13 wherein the ohmic contact to the first semiconductor region comprises a polycrystalline semiconductor region.
Claim 18
Dependent Claim
130 words
A light sensing device integrated in a monolithic integrated circuit, comprising: a substrate of a first conductivity type; an epitaxial layer of a first thickness and a second conductivity type on the substrate, containing device regions of the integrated circuit, and having a first exterior surface; a dielectric isolation wall extending through the epitaxial layer from the first exterior surface at least to the substrate, wherein the dielectric isolation wall has a depth from the first surface exceeding the first thickness; an intrinsic semiconductor region electrically contacting the substrate and laterally separated from the device regions of the integrated circuit by the isolation wall, and having a second exterior surface; and a first doped semiconductor region of the second type electrically contacting the intrinsic region at the second exterior surface.
Claim 19
Dependent Claim
130 words
A light sensing device integrated in a monolithic integrated circuit, comprising: a substrate of a first conductivity type; an epitaxial layer of a first thickness and a second conductivity type on the substrate, containing device regions of the integrated circuit, and having a first exterior surface; a dielectric isolation wall extending through the epitaxial layer from the first exterior surface at least to the substrate, wherein the dielectric isolation wall has a depth from the first surface exceeding the first thickness; an intrinsic semiconductor region electrically contacting the substrate and laterally separated from the device regions of the integrated circuit by the isolation wall, and having a second exterior surface; and a first doped semiconductor region of the second type electrically contacting the intrinsic region at the second exterior surface.
Claim 20
Dependent Claim
31 words
The light sensing device of claim 15 wherein the intrinsic region has a second thickness greater than the first thickness and the isolation wall depth at least equals the second thickness.
Claim 21
Dependent Claim
14 words
The light sensing device of claim 11 wherein the intrinsic region is formed epitaxially.
Claim 22
Dependent Claim
25 words
The light sensing device of claim 17 wherein the intrinsic region is formed epitaxially on the substrate in a cavity etched through the epitaxial layer.
References Cited (Backward Citations)
US892019A
Cited
US3378414A
Cited
UST892019I4
Cited
US3946423A
Cited
US4524375A
Cited
US4462847A
Cited
US4514748A
Cited
JPS61139061A
Cited
JPS6214478A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-05-14 | 1993-11-13 | 1994-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-14 | 1997-11-13 | 1998-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-14 | 2001-11-13 | 2002-05-15 | $7700.00 | Window Closed / Lapsed |