Photodiode Anti-Reflection Structure for High-Linearity Sensing
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Solution Overview
Problem
Conventional photodiode manufacturing processes face challenges in maintaining high linearity due to material degradation caused by high temperature environments during anti-reflection layer formation, affecting sensing performance.
Innovation Solution
The method involves forming a first anti-reflection layer using a high-temperature LPCVD process followed by an ion implantation process to create a second semiconductor layer, and then forming a second anti-reflection layer using a low-temperature PVD process, ensuring the second semiconductor layer is not affected by high temperatures, thereby maintaining linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-temperature process is used to form the anti-reflection layer, then the anti-reflection layer can be successfully formed with proper material properties, but the semiconductor layer is affected by high temperature causing material changes and degradation of linearity
Solution Approach 1:
The patent applies preliminary action by forming the anti-reflection layer on the first semiconductor layer before forming the second semiconductor layer. This sequence ensures that the high-temperature coating process occurs before the temperature-sensitive second semiconductor layer is introduced, preventing thermal damage while maintaining proper anti-reflection layer formation
Solution Approach 2:
The patent segments the manufacturing process into distinct stages: first forming the anti-reflection layer on the first semiconductor layer, then forming the second semiconductor layer in a separate, temperature-controlled ion implantation process. This segmentation isolates the high-temperature step from the temperature-sensitive layer formation
2Manufacturing precision
If the second semiconductor layer is formed before the anti-reflection layer, then the sensing performance can be maintained, but the anti-reflection layer formation process cannot be performed at high temperature
Solution Approach 1:
The patent performs the anti-reflection layer formation as a preliminary action before creating the second semiconductor layer. This allows the high-temperature coating process to occur without compromising the second semiconductor layer, while still achieving the desired anti-reflection properties
Solution Approach 2:
The patent changes the temporal parameter of the manufacturing process by reversing the conventional sequence. Instead of forming semiconductor layers first and then the anti-reflection layer, it forms the anti-reflection layer first, then the semiconductor layers, thereby changing the process parameters to avoid thermal damage
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 approach prevents material degradation and maintains the original sensing performance of the photodiode structure by isolating the second semiconductor layer from high-temperature processes, ensuring high linearity and stability.
Implementation Method 1
performing a first coating process to form a first anti-reflection layer on the first semiconductor layer, wherein the first coating process is a high temperature LPCVD process
Implementation Method 2
performing an ion implantation process to pass through the first anti-reflection layer and form a second semiconductor layer in the recessed portion
Implementation Method 3
performing a second coating process to form a second anti-reflection layer on the first anti-reflection layer, wherein the second coating process is a PVD process
Data Source
AI summary
The present invention provides a manufacturing method of a photodiode structure. The method includes the following steps: providing a substrate; performing an epitaxial process to form a first semiconductor layer on the substrate; performing an active area patterning and etching process to form a recessed portion on the first semiconductor layer; performing a first coating process to form a first anti-reflection layer on the first semiconductor layer; and performing an ion implantation process to pass through the first anti-reflection layer and form a second semiconductor layer in the recessed portion.