Solid-State Imaging Element Leakage Suppression via Impurity Layer
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Solution Overview
Problem
In solid-state imaging elements, both junction leakage and diffusion leakage occur due to the RST Drain voltage being lower than the depletion potential of the PD and pixel transistor, leading to h+ dark current in the ED or e− dark current in the PD region, and a strong electric field causing junction leakage between the FD and Pwell or STI regions.
Innovation Solution
A solid-state imaging element configuration with a photodiode, photoelectric conversion film, and a diffusion layer, where the photodiode and diffusion layer are disposed on the same substrate, and an impurity layer with a first polarity is placed below the diffusion layer, either at a higher concentration than 2.00 E+15/cm2 or with a predetermined substance, to suppress both junction and diffusion leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If element isolation such as STI is used to separately dispose FD, PD, and pixel transistor, then junction leakage is suppressed, but device complexity increases
Solution Approach 1:
The patent merges the functions of element isolation and diffusion leakage suppression by integrating the P-type impurity layer into the existing STI structure. The impurity layer is formed in the same manufacturing process steps as the STI isolation regions, combining multiple functions (isolation and leakage suppression) into a single structural element, thereby reducing device complexity while maintaining effectiveness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces diffusion leakage and junction leakage, allowing for improved dark current suppression and preventing both types of leakage in FD storage sensors.
Implementation Method 1
a photodiode that performs photoelectric conversion on the basis of the amount of incident light
Implementation Method 2
a photoelectric conversion film that performs photoelectric conversion on the basis of the amount of incident light
Data Source
AI summary
The present technology relates to a solid-state imaging element, a solid-state imaging element manufacturing method, and an electronic apparatus that make it possible to suppress both junction leakage and diffusion leakage of an FD in an FD storage sensor. The present technology includes a photodiode, a photoelectric conversion film, a diffusion layer, and an impurity layer. The photodiode and the photoelectric conversion film perform photoelectric conversion of incident light. The diffusion layer has a second polarity, which is different from a first polarity possessed by the photodiode, and stores an electric charge derived from photoelectric conversion by the photoelectric conversion film. The impurity layer includes impurities having the first polarity. The photodiode and the diffusion layer are disposed on an identical substrate in parallel with each other. The impurity layer is disposed below the diffusion layer. The present technology is applicable to solid-state imaging elements.