Multi-Layer Photodiode Structure for Extended Quantum Length
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Solution Overview
Problem
The performance of photodiode structures in optoelectronic devices is limited by the short quantum length of single-layer quantum material layers, leading to reduced sensitivity and energy conversion efficiency.
Innovation Solution
A multi-layer photodiode structure is developed, featuring multiple sensing structures formed from quantum effect materials, with overlapping portions and sidewalls in contact with the substrate, increasing the quantum length compared to single-layer structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer photodiode structure is used, then the device complexity is low, but the quantum length is insufficient which reduces sensitivity and energy conversion efficiency
Solution Approach 1:
The patent transitions from a single-layer planar photodiode structure to a multi-layer three-dimensional structure. By stacking multiple quantum material layers vertically, the effective quantum length is extended without increasing the lateral footprint, thereby enhancing light absorption and energy conversion efficiency while maintaining compact device dimensions.
Solution Approach 2:
The photodiode structure is divided into multiple discrete quantum material layers separated by spacer layers. Each layer acts as an independent sensing element, and the collective stacking creates an extended quantum length. This segmentation allows for improved light absorption while maintaining manufacturability through standardized layer deposition processes.
2Reliability
If the quantum material layer thickness is increased to improve sensitivity, then energy conversion efficiency improves, but manufacturing precision becomes more difficult to control
Solution Approach 1:
Instead of depositing a single thick quantum material layer that is difficult to control, the patent segments the total thickness into multiple thinner layers. Each layer can be deposited with precise thickness control using standard semiconductor fabrication processes, while the cumulative thickness achieves the desired quantum length for high energy conversion efficiency.
Solution Approach 2:
Spacer layers are introduced as intermediary structures between quantum material layers. These spacer layers serve as etch stop layers during manufacturing, providing precise thickness control and separation. The spacers enable accurate positioning and spacing of quantum layers, ensuring manufacturing precision while maintaining the extended quantum length needed for high efficiency.
3Reliability
If a multi-layer photodiode structure is implemented, then sensitivity and quantum length are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The spacer layers serve multiple functions: they act as etch stop layers during etching processes, provide separation between quantum material layers, and define the precise spacing and positioning. This multi-functionality simplifies the manufacturing process by reducing the need for additional process steps while achieving the desired multi-layer structure with improved performance.
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
The multi-layer photodiode structure enhances the performance of optoelectronic devices by increasing sensitivity and energy conversion efficiency, improving manufacturing yield, and reducing field failures.
Implementation Method 1
Complementary metal oxide semiconductor (CMOS) image sensor (CIS) devices utilize light-sensitive CMOS circuitry to convert light energy into electrical energy. As the photodiode structure is exposed to light, an electrical charge is induced in the photodiode structure (referred to as a photocurrent).
Implementation Method 2
Photons from light entering the layer of the quantum material may be absorbed and create electron-hole pairs that are separated by the electric field across a p-n junction, generating a current
Data Source
AI summary
Some implementations described herein provide an optoelectronic device including a multi-layer photodiode structure having multiple sensing structures formed from one or more quantum effect materials (e.g., formed from multiple layers of quantum effect materials). The multiple sensing structures, which include sidewalls that are in contact with a substrate of the optoelectronic device, may be stacked and include overlapping portions. Through use of the multi-layer photodiode structure including the multiple sensing structures, a quantum length is increased relative to another photodiode structure including a single, planar sensing structure formed from a layer of a quantum effect material.