GaN UV Detector Schottky Junction Reliability
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Solution Overview
Problem
GaN-based UV light detection devices face challenges in reproducibility and detection accuracy due to defects in the buffer layer and light absorption layer, leading to variations in photocurrent characteristics and UV photo-reactivity, as well as current leakage issues affecting the Schottky junction's efficiency.
Innovation Solution
A UV light detection device is designed with a capping layer having a higher energy bandgap than the light absorption layer, which improves Schottky characteristics, reduces leakage current, and enhances electrostatic discharge (ESD) properties by blocking non-UV light reactions, thereby improving the device's photo-reactivity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal layer is grown on the light absorption layer to form a Schottky junction, then the device structure is established, but UV photo-reactivity deteriorates and current leakage occurs depending on Schottky layer thickness and interfacial characteristics
Solution Approach 1:
An AlN layer is introduced as an intermediary between the light absorption layer and the Schottky contact layer. This intermediate layer improves the Schottky junction characteristics by providing a better interface, reducing current leakage, and enhancing the overall reliability of the UV photodetection device while maintaining UV photo-reactivity.
2Ease of manufacture
If the light absorption layer is grown on the buffer layer having many defects, then the device structure is formed, but photocurrent characteristics vary and UV photo-reactivity changes due to uneven defect density
Solution Approach 1:
The AlN layer serves as a mediator between the defective buffer layer and the light absorption layer, isolating the defects in the buffer layer from affecting the light absorption layer. This results in more consistent photocurrent characteristics and UV photo-reactivity across devices fabricated on the same wafer.
3Adaptability or versatility
If a Schottky junction structure is fabricated with metal layer on light absorption layer, then the device functionality is achieved, but UV photo-reactivity and current leakage depend on Schottky layer thickness
Solution Approach 1:
The AlN intermediate layer decouples the relationship between Schottky layer thickness and UV photo-reactivity, allowing for more consistent photo-reactivity characteristics regardless of the specific Schottky layer thickness used in fabrication.
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 solution enhances the UV light detection device's Schottky characteristics, increases its ability to withstand reverse bias, and improves the detection efficiency and reliability by minimizing leakage current and optimizing the response to UV light while reducing sensitivity to visible light.
Implementation Method 1
a capping layer having a higher energy bandgap than a light absorption layer to improve photo-reactivity and leakage current characteristics
Implementation Method 2
GaN-based photodetection device includes a buffer layer grown on a heterogeneous substrate and a light absorption layer formed on the buffer layer
Implementation Method 3
a Schottky layer disposed in a partial region of the capping layer, wherein the capping layer has a higher energy bandgap than the light absorption layer
Data Source
AI summary
An ultraviolet ray detecting device is provided. The ultraviolet ray detecting device comprises: a substrate; a buffer layer disposed on the substrate; a light absorption layer disposed on the buffer layer; a capping layer disposed on the light absorption layer; and a Schottky layer disposed on a partial region of the capping layer, wherein the capping layer has an energy bandgap larger than that of the light absorption layer.