Rounded Active-Region Gate Structure for Low-Noise Image Sensors
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Solution Overview
Problem
Highly integrated image sensors with miniaturized pixel sizes face challenges in maintaining stable electrical characteristics and low-luminance resolution due to noise issues and limited voltage constraints.
Innovation Solution
The image sensor design incorporates a substrate with a pixel region featuring a gate electrode structure that includes a local round edge portion with a greater radius of curvature than other edge portions, enhancing channel area and ensuring a required level of limit voltage, thereby improving noise characteristics and electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If image sensors are highly integrated and pixel size is miniaturized, then integration density increases, but noise characteristics deteriorate and electrical stability decreases
Solution Approach 1:
The patent applies local quality by creating a local round edge portion with a greater radius of curvature at specific locations within the active region, while other portions maintain normal edge geometry. This localized structural modification improves noise characteristics and electrical stability in critical areas without compromising the overall miniaturization and high integration density of the image sensor.
2Measurement precision
If pixel size is miniaturized, then resolution increases, but channel area of transistor decreases leading to poor electrical properties
Solution Approach 1:
The patent utilizes spheroidality by forming a local round edge portion with a greater radius of curvature in the active region. This curved geometry increases the channel area of the transistor compared to straight-edged designs, thereby improving electrical properties such as mobility and current drive while maintaining the miniaturized pixel size for high resolution.
3Ease of manufacture
If edge portion has sharp corners, then manufacturing is simpler, but electrical characteristics are unstable due to limited voltage
Solution Approach 1:
The patent applies parameter changes by modifying the radius of curvature parameter of the edge portion. The local round edge portion has a greater radius of curvature than normal edge portions, which changes the electrical field distribution and improves voltage stability and electrical characteristics while maintaining manufacturability through standard semiconductor fabrication processes.
Data Source
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AI summary
Provided are an image sensor and an electronic system including the same. An image sensor includes a substrate having a pixel region in which an active region is defined, and a gate electrode on the active region, wherein the active region includes an edge portion extending along an outline of a top surface thereof, the edge portion including a local round edge portion having a first radius of curvature that is greater than a second radius of curvature of other portions of the edge portion, wherein the gate electrode includes a lateral gate portion on a portion of the top surface of the active region, a vertical gate portion on a sidewall of the active region, and a round inner corner portion integrally connected to the lateral gate portion and the vertical gate portion, the round inner corner portion facing the local round edge portion.