GaN Radiation Detector Structure for Thick Low-Doped Drift Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing GaN-based radiation detectors face challenges with reduced efficiency, response speed, and complex structure due to thin drift layers and high impurity concentrations, primarily caused by limitations in growth methods and substrate differences, leading to decreased electron mobility and increased doping concentrations.
Innovation Solution
A GaN-based radiation detector design featuring a thick GaN substrate with low impurity concentration and high electron mobility, combined with optimized doping concentrations and layer structures, including n-doped and p-doped GaN layers, and potentially rough surfaces, to enhance efficiency and response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a thin drift layer is used in GaN-based radiation detectors, then the detector structure becomes simpler, but the detection efficiency and response speed decrease
Solution Approach 1:
The patent changes the thickness parameter of the drift layer from thin (less than 30 μm) to thick (300 μm or more), which fundamentally alters the detection performance. This parameter change allows the detector to achieve both high detection efficiency and fast response speed while maintaining a relatively simple structure, resolving the contradiction between structural simplicity and detection efficiency.
2Productivity
If the drift layer thickness is increased to improve detection efficiency, then the response speed improves, but the doping concentration must be increased which reduces electron mobility
Solution Approach 1:
The patent optimizes the doping concentration parameter to 3×10^16/cm³ or less for the thick drift layer, which maintains high electron mobility despite the increased thickness. This careful parameter selection allows the detector to achieve both high detection efficiency and fast response speed without sacrificing electron mobility, resolving the contradiction between detection efficiency and electron mobility.
3Ease of manufacture
If GaN is grown on sapphire or silicon carbide substrates using MOCVD process, then the manufacturing process is convenient, but the growth thickness is limited to less than 30 μm causing reduced efficiency
Solution Approach 1:
The patent changes the thickness parameter from less than 30 μm to 300 μm or more, overcoming the limitation of conventional MOCVD growth on sapphire or silicon carbide substrates. This parameter change enables the detector to achieve high detection efficiency while maintaining the convenience of MOCVD manufacturing processes, resolving the contradiction between ease of manufacture and detection efficiency.
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 proposed design improves detector efficiency and response speed while simplifying the structure, reducing manufacturing costs, and increasing breakdown voltage, with enhanced electron transport and radiation absorption.
Implementation Method 1
a drift layer, which is the region where electrons and holes are generated by the incident radiation
Implementation Method 2
a first metal contact formed on the other surface of the n-doped GaN layer; and a second metal contact formed on one surface of the p-doped GaN layer
Data Source
AI summary
The present invention relates to a GaN-based radiation detector capable of detecting radiation such as X-rays. The GaN-based radiation detector includes: an n-doped GaN layer having an electron mobility of 700 cm2/(V·s) or more and a thickness of 300 μm or more and doped with an n-type doping concentration of 3×1016/cm3 or less; a p-doped GaN layer formed on one surface of the n-doped GaN layer and having a thickness of 3 μm or less and doped with a p-type doping concentration of 5×1018/cm3 or more; a first metal contact formed on the other surface of the n-doped GaN layer; and a second metal contact formed on one surface of the p-doped GaN layer.