Omnivision Technologies, Inc.

Yuanwei Zheng

Gang Chen

Dyson Hsinchih Tai

Duli Mao

Lindsay Alexander Grant

Chih-Wei Hsiung

Arvind Kumar

Sing-Chung Hu

Qin Wang

Cunyu Yang

Guannan Chen

Yi Ma

Shiyu Sun

Lequn Liu

Yin Qian

Bill Phan

Zhiqiang Lin

Dominic Massetti

Xianmin Yi

Chia-Chun Miao

Chao Niu

Eric Webster

Chiao-Ti Huang

Hung Chih Chang

Armin Yazdani

A pixel array includes 2×2 groupings of photodiodes to generate image charge in response to incident light directed through a back side of the semiconductor layer. A Quad Bayer filter is disposed over the back side of the semiconductor layer over the 2×2 groupings of photodiodes. Each color filter of the Quad Bayer CFA is disposed over a respective one of the plurality of 2×2 groupings of photodiodes. Trench balance structures are disposed in the semiconductor layer. Each of the trench balance structures is disposed in the semiconductor layer between one of the photodiodes and a respective one of the red color filters of the Quad Bayer filter. None of the trench balance structures are disposed between any of the photodiodes and respective green color filters or blue color filters of the Quad Bayer filter.

Trench balance structure pattern in red photodiodes of a pixel array with quad bayer color filter

An image sensor includes a photodiode disposed in a semiconductor substrate having a first surface and a second surface opposite to the first surface. A floating diffusion is disposed in the semiconductor substrate. A transfer transistor is configured for coupling the photodiode to the floating diffusion. The transfer transistor includes a vertical transfer gate extending a first depth in a depthwise direction from the first surface into the semiconductor substrate. A transistor is coupled to the floating diffusion. The transistor includes: a planar gate disposed proximate to the first surface of the semiconductor substrate; and a plurality of vertical gate electrodes, each extending a respective depth into the semiconductor substrate from the planar gate in the depthwise direction. The respective depth of at least one of the plurality of vertical gate electrodes is the same as the first depth of the vertical transfer gate.

Transistors having increased effective channel width

A pixel cell is formed on a semiconductor substrate having a front surface. The pixel cell includes a photodiode, a floating diffusion region, and a transfer gate. The photodiode is disposed in the semiconductor substrate. The floating diffusion region includes a first doped region disposed in the semiconductor substrate, wherein the first doped region extends from the front surface to a first junction depth in the semiconductor substrate. The transfer gate is configured to selectively couple the photodiode to the floating diffusion region controlling charge transfer between the photodiode and the floating diffusion region. The transfer gate includes a planar gate disposed on the front surface of the semiconductor substrate and a pair of vertical gate electrodes. Each vertical gate electrode extending a gate depth from the planar gate into the semiconductor substrate. The first junction depth is greater than the gate depth.

Pixel cell having anti-blooming structure and image sensor

An image sensor includes a semiconductor substrate and a multilayer film. The semiconductor substrate includes a photodiode and a back surface having a recessed region that surrounds the photodiode. The multilayer film is on, and conformal to, the recessed region, and includes N layer-groups of adjacent high-κ material layers. Each pair of adjacent high-κ material layers of a same layer-group of the N layer-groups includes (i) an outer-layer having an outer fixed-charge density and (ii) an inner-layer, located between the outer-layer and the recessed region, that has an inner fixed-charge density. Each of the outer and inner fixed-charge density is negative. The inner fixed-charge density is more negative than the outer fixed-charge density.

Passivation-enhanced image sensor and surface-passivation method

A pixel-array substrate includes a semiconductor substrate with a pixel array, a back surface, and a front surface, and a guard ring formed of a doped semiconductor, enclosing the pixel array, and extending into the semiconductor substrate from the front surface, the back surface forming a trench extending into the semiconductor substrate, the trench overlapping the guard ring. A method for reducing leakage current into a pixel-array includes doping a semiconductor substrate to form a guard ring that extends into the semiconductor substrate from a front surface, encloses a pixel array, excludes a periphery region, and resists a flow of electric current, and forming, into a back surface of the semiconductor substrate, a trench that penetrates into the back surface and overlaps the guard ring, the guard ring and the trench configured to resist the flow of electric current between the pixel array and the periphery region.

Electrical isolation in pixel-array substrates using combination of doped semiconductor guard rings and overlapping isolation trenches

An image sensor includes a substrate. An array of photodiodes is disposed in the substrate. A plurality of spacers is arranged in a spacer pattern. At least one spacer of the plurality of spacers has an aspect ratio of 18:1 or greater. A buffer layer is disposed between the substrate and the spacer pattern. An array of color filters is disposed in the spacer pattern.

Fully buried color filter array of image sensor

An image sensor includes one or more photodiodes disposed in a semiconductor material to receive image light and generate image charge, and a floating diffusion to receive the image charge from the one or more photodiodes. One or more transfer transistors is coupled to transfer image charge in the one or more photodiodes to the floating diffusion, and a source follower transistor is coupled to amplify the image charge in the floating diffusion. The source follower includes a gate electrode (coupled to the floating diffusion), source and drain electrodes, and an active region disposed in the semiconductor material between the source and drain electrodes. A dielectric material is disposed between the gate electrode and the active region and has a first thickness and a second thickness. The second thickness is greater than the first thickness, and the second thickness is disposed closer to the drain electrode than the first thickness.

Image sensor having a source follower transistor with a multi-thickness gate dielectric

An image sensor pixel includes a photodiode disposed in a semiconductor material to generate image charge in response to light incident on a backside of the semiconductor material, and a pinning layer disposed in the semiconducting material and coupled to the photodiode. The pixel also includes a vertical overflow drain disposed in the semiconductor material and coupled to the pinning layer such that the pinning layer is disposed between the vertical overflow drain and the photodiode. A floating diffusion disposed in the semiconductor material proximate to the photodiode, and a vertical transfer transistor is disposed in part in the semiconductor material and coupled to the photodiode to transfer the image charge from the photodiode to the floating diffusion in response to a transfer signal applied to the gate terminal of the vertical transfer transistor.

Vertical overflow drain combined with vertical transistor

A resonant-filter image sensor includes a pixel array including a plurality of pixels and a microresonator layer above the pixel array. The microresonator layer includes a plurality of microresonators formed of a first material with an extinction coefficient less than 0.02 at a free-space wavelength of five hundred nanometers. Each of the plurality of pixels may have at least one of the plurality of microresonators at least partially thereabove. The resonant-filter image sensor may further include a layer covering the microresonator layer that has a second refractive index less than a first refractive index, the first refractive index being the refractive index of the first material. Each microresonator may be one of a parallelepiped, a cylinder, a spheroid, and a sphere.

Resonant-filter image sensor and associated fabrication method

An image sensor includes a plurality of photodiodes arranged in an array and disposed in a semiconductor material to receive light through a first surface of the semiconductor material. At least part of the semiconductor material is curved. A carrier wafer is attached to a second surface, opposite the first surface, of the semiconductor material, and a polymer layer is attached to the carrier wafer, so that the carrier wafer is disposed between the polymer layer and the semiconductor material.

Curved image sensor using thermal plastic substrate material

An image sensor includes a plurality of photodiodes disposed in a semiconductor material, and a through-semiconductor-via coupled to a negative voltage source. Deep trench isolation structures are disposed between individual photodiodes in the plurality of photodiodes to electrically and optically isolate the individual photodiodes. The deep trench isolation structures include a conductive material coupled to the through-semiconductor-via, and a dielectric material disposed on sidewalls of the deep trench isolation structures between the semiconductor material and the conductive material.

Biased deep trench isolation

A method of image sensor fabrication includes providing a semiconductor material, an insulation layer, and a logic layer, where the semiconductor material includes a plurality of photodiodes. A through-semiconductor-via is formed which extends from the semiconductor material, through the insulation layer, and into the logic layer. The through-semiconductor-via is capped with a capping layer. A metal pad is disposed in a first trench in the semiconductor material. Insulating material is deposited on the capping layer, and in the first trench in the semiconductor material. A resist is deposited in a second trench in the insulating material, and the second trench in the insulating material is aligned with the metal pad. The insulating material is removed to expose the capping layer, and a portion of the capping layer disposed proximate to the plurality of photodiodes is also removed. A metal grid is formed proximate to the plurality of photodiodes.

Growing community of inventors

San Jose, CA, United States of America

Yuanwei Zheng