Radiation Detector Induced Junction for UV and X-Ray Signal Gain
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Solution Overview
Problem
Conventional PN junction-based radiation detectors suffer from signal reduction due to an electrically dead layer and increased Auger recombination, particularly detrimental for UV and X-ray detection, where the PN junction lies deep below the surface, and existing induced junction detectors have limited performance due to material constraints.
Innovation Solution
A semiconductor radiation detector with an electric field generating layer using ferroelectric or electrically polarized materials to create a shallow PN junction with minimal doping, allowing for stronger inducing charges and improved performance by forming an inversion layer without the need for extensive doping, thereby reducing leakage current and enhancing radiation detection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PN junctions are used with deep junction depth, then the junction can be formed with moderate or heavy doping, but this creates an electrically dead layer and increases Auger recombination, reducing quantum efficiency and output signal
Solution Approach 1:
The patent changes the fundamental parameter of junction depth from deep to shallow (near-surface), and simultaneously changes the doping parameter from moderate/heavy to minimal or no doping. This is achieved through induced junctions where an inducing layer creates the PN junction effect without requiring extensive doping, thereby eliminating the electrically dead layer and reducing Auger recombination losses.
Solution Approach 2:
The patent introduces an inducing layer as an intermediary element that generates surface charge to form the induced junction. This inducing layer acts as a mediator that creates the electric field necessary for junction formation without requiring the traditional deep diffusion or implantation processes, enabling shallow junction formation with minimal doping.
2Reliability
If existing induced junction detectors use conventional dielectric materials like SiO2 or Al2O3, then the manufacturing process is simple, but the available charge range is limited resulting in weaker induced junctions and reduced device performance
Solution Approach 1:
The patent employs composite material structures combining the semiconductor substrate with advanced dielectric layers (ferroelectric materials like Pb(Zr,Ti)O3, Pb1-xLaxZr1-yTiyO3, or electric materials like SiN4). These composite structures provide both the electrical functionality for strong induced junctions and compatibility with semiconductor manufacturing processes.
Solution Approach 2:
The patent changes the material parameter of the dielectric layer from conventional materials (SiO2, Al2O3) to advanced materials with higher polarization and charge capabilities (ferroelectric and electric materials). This material parameter change enables stronger inducing charges and improved junction characteristics while maintaining manufacturability through established deposition techniques.
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 results in improved diode characteristics and performance with reduced material in the entrance window, enhancing the detection of high-energy photons like UV and X-rays by minimizing absorption and recombination losses, leading to increased quantum efficiency and signal strength.
Implementation Method 1
an electric field generating layer on a first face of the substrate, the electric field generating layer inducing electric field into the substrate for forming an inversion layer in the substrate
Implementation Method 2
the electric field generating layer comprises a dielectric layer with a polarization and/or charge for inducing the electric field
Implementation Method 3
the dielectric layer comprises at least one of: ferroelectric material, electric material, ferroelectric material
Implementation Method 4
a dielectric layer with a polarization and/or charge for inducing the electric field
Implementation Method 5
A photodiode is a semiconductor device with a P-N junction that converts photons (or light) into electrical current
Implementation Method 6
The signal reduction via absorption is especially detrimental in detection of UV and X-ray photons
Data Source
AI summary
According to an example aspect of the present invention, there is provided semiconductor radiation detectors, such as photodetectors, with a low amount of material in the radiation/photon entrance window and minimal doping of semiconductor substrate. More specifically, an induced junction based on electrically polarized materials is utilized.