Photoelectric Conversion Layer Stack for Low Noise and Dark Current
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Solution Overview
Problem
Existing photoelectric conversion apparatuses face challenges in reducing noise and dark current due to crystal defects in silicon and interface states between silicon and insulating films, while also risking oxidation of metal wiring layers during heat treatment.
Innovation Solution
The apparatus incorporates a semiconductor layer with a photoelectric conversion unit, a circuit substrate, and insulating films that allow hydrogen termination of dangling bonds, with a specific configuration of insulating films to inhibit hydrogen diffusion and prevent metal wiring oxidation, including silicon oxide, silicon carbide, and silicon nitride layers to manage hydrogen supply and diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat treatment is performed on the pixel substrate alone in a state where vias formed in an electrode pad and a dummy pad that are connected to a wiring layer including metal, then hydrogen diffusion is promoted to reduce noise and dark current, but the wiring layer including the metal is oxidized
Solution Approach 1:
A protective film is introduced as an intermediary layer between the metal wiring layer and the oxidation environment during heat treatment. This protective film allows hydrogen to pass through to terminate dangling bonds in the pixel substrate while blocking oxygen from oxidizing the metal wiring, thus resolving the contradiction between promoting hydrogen diffusion and preventing metal oxidation
Solution Approach 2:
The patent employs an inert or reducing atmosphere during heat treatment to create an environment that permits hydrogen diffusion to the pixel substrate while preventing oxidation of the metal wiring layer. This atmospheric control enables simultaneous achievement of noise reduction through hydrogen termination and protection of metal interconnects from oxidation
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 noise and dark current while preventing metal wiring oxidation, enhancing the hydrogen termination effect and increasing process flexibility by ensuring sufficient hydrogen supply to the photoelectric conversion unit.
Implementation Method 1
heat treatment process for promoting diffusion of hydrogen is performed
Implementation Method 2
uses hydrogen termination of dangling bonds for a lamination type sensor to reduce noise and dark current
Implementation Method 3
there is a possibility that the wiring layer including the metal is oxidized
Implementation Method 4
a pixel substrate including a photoelectric conversion unit
Data Source
AI summary
A photoelectric conversion apparatus includes a semiconductor layer having a front surface and a back surface and including a photoelectric conversion unit, a circuit substrate, a first insulating film, a second insulating film, a third insulating film, and a wiring layer. The first insulating film includes at least one of silicon oxide and silicon oxycarbide. The second insulating film includes at least one of silicon carbide, silicon nitride, and silicon carbonitride. A hole portion provided with a conductive material and penetrating through the first insulating film and the second insulating film is disposed. An entire end portion of the hole portion on the semiconductor layer side of the second insulating film is in contact with the third insulating film.