Omnivision Technologies, Inc.

Hui Zang

Gang Chen

Yuanliang Liu

Duli Mao

Bill Phan

Qin Wang

Zhiqiang Lin

Cunyu Yang

Chao Niu

Vincent Venezia

Keiji Mabuchi

Shiyu Sun

Seong Yeol Mun

Kenny Geng

Yifei Du

Cynthia Sun Yee Lee

Takeshi Takeda

A global-shutter pixel includes a semiconductor substrate that has a storage node and a photodiode region. A front surface of the substrate has a first recessed region between the photodiode region and the storage node in a first direction parallel to the front surface, and a second recessed region between the first recessed region and the storage node in the first direction. The first and second recessed regions extend into the substrate to a respective first recess-depth and a second recess-depth that exceeds the first recess-depth. The photodiode region includes (i) a first doped-section spanning a depth-range and having a first dopant concentration, and (ii) a second doped-section between the front surface and the first doped-section and having a second dopant concentration that is less than the first dopant concentration. The first doped-section includes a protrusion that extends at least partially beneath the first recessed region in the first direction.

Global-shutter pixel

A pixel of an image sensor includes a semiconductor substrate having a front surface and a back surface opposing the front surface, a photodiode and floating diffusion (FD) region formed in the substrate along a first pixel axis parallel to the front surface and a transfer gate formed in the front surface of the substrate between the photodiode and the FD region. The transfer gate includes a planar gate on the front surface of the substrate, a vertical transfer gate extending into the substrate from the planar gate, the vertical transfer gate further including a trench and a layer of doped semiconductor material epitaxially grown on the sides and bottom of the trench. The semiconductor substrate and the epitaxial layer comprise a first conductive type, and the photodiode and the FD region comprise a second conductive type. An image sensor and method of forming the vertical transfer gate are disclosed.

Pixel with vertical transfer structure for dark current improvement, an image sensor thereof and a fabrication method thereof

Image sensors include a pixel array arranged about an array center, each pixel of the pixel array having a photodiode formed in a semiconductor substrate, and a central deep trench isolation structure disposed in the semiconductor substrate relative to a pixel center between the photodiode and an illuminated surface of the semiconductor substrate. If the pixel center is not coincident with the array center, then the central deep trench isolation structure is disposed at a CDTI shift distance away from the pixel center.

Central deep trench isolation shift

A backside-illuminated image sensor includes photodiodes in photodiode regions electrically isolated by filled trenches with openings in a dielectric layer over the photodiodes. The image sensor has a metal grid aligned over the trenches, the metal grid within 80 nanometers of the trenches. The image sensor is formed by: fabricating photodiodes in photodiode regions of a frontside of a silicon substrate with source-drain regions of transistors, the photodiodes electrically isolated by deep trenches, each photodiode within a photodiode region of the substrate; forming the filled trenches in a backside of the semiconductor substrate; forming protective oxide and process stop layers over the backside of the semiconductor substrate; depositing a metal grid over the deep trenches, removing the process stop layer from over photodiode regions; and depositing color filters over the photodiode regions.

High dynamic range, backside-illuminated, low crosstalk image sensor with walls on backside surface to isolate photodiodes

A pixel for an image sensor is described. The pixel comprises a photodiode and an isolation structure disposed within a semiconductor substrate and between a first and second side of the semiconductor substrate. The isolation structure includes a bottom sidewall coupled to a first sidewall and a second sidewall of the isolation structure. The isolation structure is disposed, at least in part, between a gate electrode and the second side of the semiconductor substrate. A first implant region of the semiconductor substrate is disposed proximate to the first sidewall of the isolation structure. The first implant region is disposed between the photodiode and the first sidewall. A first dopant concentration of the first implant region is greater than a bulk dopant concentration of the semiconductor substrate.

CMOS devices with asymmetrically passivated isolation structure and methods thereof

Image sensors, isolation structures, and techniques of fabrication are provided. An image sensor includes a source of electromagnetic radiation disposed on a substrate, a pixel array disposed on the substrate and thermally coupled with source of electromagnetic radiation, and an isolation structure disposed on the substrate between the source of electromagnetic radiation and the pixel array. The isolation structure can define a first reflective surface oriented on a first bias relative to a lateral axis of the pixel array and a second reflective surface oriented on a second bias relative to the lateral axis. The isolation structure can be configured to attenuate residual electromagnetic radiation reaching a proximal region of the pixel array by pairing a first reflection and a second reflection of the electromagnetic radiation by the first reflective surface and the second reflective surface.

Image sensor diagonal isolation structures

Transistors, electronic devices, and methods are provided. Transistors include a gate trench formed in a semiconductor substrate and extending to a gate trench depth, and a source and a drain formed as doped regions in the semiconductor substrate and having a first conductive type. The source and the drain are formed along a channel length direction of the transistor at a first end and a second end of the gate trench, respectively, and the source and the drain each includes a first doped region and a second doped region extending away from the first doped region. The second doped region extends to a depth in the semiconductor substrate deeper than the first doped region relative to a surface of the semiconductor substrate.

Dual depth junction structures and process methods

Transistors having nonplanar electron channels in the channel width plane have one or more features that cause the different parts of the nonplanar electron channel to turn on at substantially the same threshold voltage. Advantageously, such transistors have substantially uniform threshold voltage across the nonplanar electron channel. Devices, image sensors, and pixels incorporating such transistors are also provided, in addition to methods of manufacturing the same.

Uniform threshold voltage non-planar transistors

A dark-current-inhibiting image sensor includes a semiconductor substrate, a thin and a thin junction. The semiconductor substrate includes a front surface, a back surface opposite the front surface, a photodiode, and a concave surface between the front surface and the back surface. The concave surface extends from the back surface toward the front surface, and defines a trench that surrounds the photodiode in a cross-sectional plane parallel to the back surface. The thin junction extends from the concave surface into the semiconductor substrate, and is a region of the semiconductor substrate. The semiconductor substrate includes a first substrate region, located between the thin junction and the photodiode, that has a first conductive type. The photodiode and the thin junction have a second conductive type opposite the first conductive type.

Dark-current inhibiting image sensor and method

An image sensor comprises a first photodiode region and circuitry. The first photodiode region is disposed within a semiconductor substrate proximate to a first side of the semiconductor substrate to form a first pixel. The first photodiode region includes a first segment coupled to a second segment. The circuitry includes at least a first electrode associated with a first transistor. The first electrode is disposed, at least in part, between the first segment and the second segment of the first photodiode region such that the circuity is at least partially surrounded by the first photodiode region when viewed from the first side of the semiconductor substrate.

Pixel layout with photodiode region partially surrounding circuitry

A method for forming a contact pad of a semiconductor device is disclosed. The method includes providing a semiconductor substrate including a first side and a second side. The semiconductor device includes a shallow trench isolation structure, disposed between the first side and the second side, and an intermetal dielectric stack coupled to the second side. The intermetal dielectric stack includes a first metal interconnect. The method further includes etching a first trench into the semiconductor substrate, depositing a dielectric material into the first trench to form a dielectric spacer extending along side walls of the first trench, etching a second trench aligned with the first trench, and depositing a metal material into the second trench to form the contact pad that contacts the first metal interconnect.

Semiconductor device contact pad and method of contact pad fabrication

Pixels, such as for image sensors and electronic devices, include a photodiode formed in a semiconductor substrate, a floating diffusion, and a transfer structure selectively coupling the photodiode to the floating diffusion. The transfer structure includes a transfer gate formed on the semiconductor substrate, and a vertical channel structure including spaced apart first doped regions formed in the semiconductor substrate between the transfer gate and the photodiode. Each spaced apart first doped region is doped at a first dopant concentration with a first-type dopant. The spaced apart first doped regions are formed in a second doped region doped at a second dopant concentration with a second-type dopant of a different conductive type.

Vertical transfer structures

Process to release Silicon stress in forming CMOS image sensor. In one embodiment, a method for manufacturing an image sensor includes providing a first wafer that is a semiconductor substrate, where the first wafer has a first side and a second side opposite from the first side. The method also includes attaching a second wafer to the second side of the first wafer. The method further includes forming isolation structures in the second wafer by etching. The isolation structures are bounded by the second side of the first wafer. The method also includes growing an epitaxial layer between individual isolation structures.

Process to release silicon stress in forming CMOS image sensor

An uneven-trench pixel cell includes a semiconductor substrate that includes a floating diffusion region, a photodiode region, and, between a front surface and a back surface: a first sidewall surface, a shallow bottom surface, a second sidewall surface, and a deep bottom surface. The first sidewall surface and a shallow bottom surface define a shallow trench, located between the floating diffusion region and the photodiode region, that extends into the semiconductor substrate from the front surface. A shallow depth of the shallow trench exceeds a junction depth of the floating diffusion region. The second sidewall surface and a deep bottom surface define a deep trench, located between the floating diffusion region and the photodiode region, that extends into the semiconductor substrate from the front surface. A distance between the deep bottom surface and the front surface defines a deep depth, of the deep trench, that exceeds the shallow depth.

Uneven-trench pixel cell and fabrication method

A pixel includes a semiconductor substrate, a low-&#x3ba; dielectric, and a photodiode region in the semiconductor substrate. The semiconductor substrate has a substrate top surface that forms a trench. The trench extends into the semiconductor substrate and has a trench depth relative to a planar region of the substrate top surface surrounding the trench. The low-&#x3ba; dielectric is in the trench between the trench depth and a low-&#x3ba; depth with respect to the planar region. The low-&#x3ba; depth is less than the trench depth. The photodiode region is in the semiconductor substrate and includes (i) a bottom photodiode section beneath the trench and (ii) a top photodiode section adjacent to the trench. The top photodiode section begins at a photodiode depth, with respect to the planar region, that is less than the low-&#x3ba; depth, and extends toward and adjoining the bottom photodiode section.

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San Jose, CA, United States of America

Hui Zang