Segmented Radiation Detector With Trench Isolation
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Solution Overview
Problem
Conventional radiation detectors face challenges in minimizing edge extension without increasing fabrication complexity, particularly in achieving efficient radiation detection with semiconductor-based detectors.
Innovation Solution
The design incorporates a semiconductor substrate with a trench extending through its entire thickness, where the sidewall is doped and only the doped sidewall is exposed to radiation, coupled with an electronic system that includes a voltage comparator and capacitor module to process charge carriers generated by radiation absorption, ensuring minimal current leakage and efficient photon counting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional radiation detectors are designed to minimize edge extension, then detection efficiency is improved, but fabrication complexity increases
Solution Approach 1:
The detector is segmented into discrete regions separated by trenches, with each region having its own electrode. This segmentation allows for minimized edge extension between regions while maintaining simple fabrication processes for each individual region, resolving the contradiction between detection efficiency and fabrication complexity
Solution Approach 2:
Different regions of the detector are designed with locally optimized properties, including varying trench depths and doping concentrations tailored to specific detection requirements. This local quality approach enables high detection efficiency in critical areas while keeping overall fabrication complexity manageable through standardized processes
2Measurement precision
If trenches are formed through the entire thickness of the semiconductor substrate, then edge extension is reduced, but manufacturing complexity increases
Solution Approach 1:
The continuous substrate is divided into discrete regions by trenches that extend through the entire thickness, creating isolated detection areas with minimized edge effects. This segmentation achieves precise edge extension control while the trenches themselves are formed using standard semiconductor fabrication techniques, balancing manufacturing complexity
Solution Approach 2:
The trench structure introduces a vertical dimension to edge control, extending trenches through the thickness of the substrate to create three-dimensional isolation between regions. This dimensional approach provides superior edge extension control compared to surface-level techniques, while the trench formation processes remain compatible with existing manufacturing capabilities
3Reliability
If sidewalls are doped to prevent current leakage, then detection reliability is improved, but device complexity increases
Solution Approach 1:
Doping is applied locally to the sidewalls of trenches rather than uniformly across the entire device. This localized doping strategy prevents current leakage at critical interfaces between regions while maintaining simpler device structures in non-critical areas, resolving the contradiction between reliability and device complexity
Solution Approach 2:
Sidewall doping is performed as a preliminary step during the fabrication process, before final device assembly and operation. This preliminary action ensures that current leakage prevention measures are built into the device structure from the outset, improving reliability without requiring additional complex components or post-processing steps
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 reduces edge extension while maintaining high detection efficiency, ensuring that charge carriers generated by radiation are effectively collected and counted, enhancing the detector's ability to accurately measure radiation without substantial sharing between discrete regions.
Implementation Method 1
a semiconductor layer that absorbs the radiation and generate charge carriers (e.g., electrons and holes)
Implementation Method 2
doping a sidewall of the trench
Data Source
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Figure 2B
AI summary
Disclosed herein is a method for forming a radiation detector. The method comprises forming a radiation absorption layer and bonding an electronics layer to the radiation absorption layer. The electronics layer comprises an electronic system configured to process electrical signals generated in the radiation absorption layer upon absorbing radiation photons. The method for forming the radiation absorption layer comprises forming a trench into a first surface of a semiconductor substrate; doping a sidewall of the trench; forming a first electrical contact on the first surface; forming a second electrical contact on a second surface of the semiconductor substrate. The second surface is opposite the first surface. The method further comprises dicing the semiconductor substrate along the trench.