Radiation Hardened Semiconductor Pillar Structures
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Solution Overview
Problem
Conventional radiation conversion devices based on PIN diodes become less sensitive over time due to radiation damage, leading to a decrease in detection sensitivity and efficiency, and their manufacturing processes are complex and costly.
Innovation Solution
The implementation of a radiation conversion device with semiconductor portions featuring first compensation zones of a specific conductivity type arranged in pillar structures, separated by second compensation zones of a complementary conductivity type, which are introduced through epitaxial growth and annealing, allowing for efficient charge carrier depletion and simplified manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PIN diode structures are used for radiation conversion, then the device can perform basic radiation detection, but the detection sensitivity decreases over time due to radiation damage
Solution Approach 1:
The semiconductor structure is segmented into alternating pillar regions (first conductivity type) and inter-pillar regions (second conductivity type), creating a multi-region compensated structure. This segmentation allows different regions to handle different aspects of radiation damage compensation, maintaining detection sensitivity over extended operational periods
Solution Approach 2:
Different regions of the semiconductor are doped with different conductivity types (first and second conductivity types) to create localized compensation zones. The pillar regions and inter-pillar regions have distinct electrical properties that locally compensate for radiation-induced defects, preserving overall device sensitivity throughout its lifetime
2Reliability
If conventional manufacturing processes are used, then basic device functionality is achieved, but the manufacturing process is complex and costly
Solution Approach 1:
Multiple doping steps and processing stages are merged into a unified epitaxial growth process that simultaneously creates both first and second conductivity type regions. This consolidation reduces the number of separate manufacturing steps while maintaining the complex compensated structure needed for high performance
Solution Approach 2:
The manufacturing process utilizes controlled changes in epitaxial growth parameters (temperature, pressure, gas flow, dopant concentration) to create different conductivity type regions in a single continuous process. By varying these parameters during growth, the complex multi-region structure is achieved without requiring multiple discrete 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 design enhances the radiation detection sensitivity and ruggedness of the device, while reducing the complexity and cost of manufacturing by minimizing the number of epitaxial layers and anneal time required.
Implementation Method 1
The grown semiconductor layers are annealed to form first compensation zones from the introduced impurities
Implementation Method 2
The semiconductor layers are annealed to form first compensation zones from the introduced impurities
Implementation Method 3
growing by epitaxy a sequence of semiconductor layers on a semiconductor substrate
Data Source
AI summary
A radiation conversion device such as a photovoltaic cell, a photodiode or a semiconductor radiation detection device, includes a semiconductor portion with first compensation zones of a first conductivity type and a base portion that separates the first compensation zones from each other. The first compensations zones are arranged in pillar structures. Each pillar structure includes spatially separated first compensation zones and extends in a vertical direction with respect to a main surface of the semiconductor portion. Between neighboring ones of the pillar structures the base portion includes second compensation zones of a second conductivity type, which is complementary to the first conductivity type. The radiation conversion device combines high radiation hardness with cost effective manufacturing.