Amorphous-to-Monocrystalline Semiconductor Layer Transformation
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Solution Overview
Problem
Semiconductor-based radiation detectors face challenges in achieving a thin, robust design that maintains signal quality and prevents space charge regions from reaching the backside contact metallization, especially when detecting high-energy particles, as existing methods often require high-temperature processes that can introduce defects and reduce detector reliability.
Innovation Solution
A method involving the formation of a semiconductor device with a lightly doped region and a highly doped region, where the highly doped region is created by transforming an amorphous semiconductor layer into a monocrystalline layer at relatively low temperatures, preventing space charge regions from bordering into the backside contact metallization and maintaining breakdown voltage and reducing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thicker radiation detector is used, then robustness to radiation improves, but signal quality deteriorates
Solution Approach 1:
The patent applies local quality by creating a highly doped region specifically at the backside of the semiconductor substrate. This localized doping modification allows the bulk substrate to remain thin for good signal quality while the localized highly doped region provides the necessary robustness and field termination, resolving the contradiction between thickness and radiation hardness.
Solution Approach 2:
The patent changes the doping concentration parameter locally at the backside, creating a highly doped region with doping levels significantly higher than the bulk. This parameter change enables the thin substrate to achieve adequate breakdown voltage and space charge region containment, resolving the contradiction between thinness and radiation robustness.
2Manufacturing precision
If high-temperature processes are used to form highly doped regions, then doping effectiveness improves, but defect formation increases
Solution Approach 1:
The patent changes the temperature parameter from conventional high-temperature processes to a lower temperature range (below 500°C). This parameter change is achieved through in-situ doping during amorphous silicon layer deposition, which allows effective doping without the thermal damage that would reduce detector reliability.
3Measurement precision
If a thinner radiation detector is produced, then signal quality improves, but manufacturing uniformity and reliability become more difficult to achieve
Solution Approach 1:
The patent applies preliminary action by forming the highly doped region through in-situ doping during the amorphous silicon layer deposition process. This preliminary doping action ensures uniform and reliable manufacturing of thin detectors, as the doping occurs simultaneously with the layer formation rather than requiring subsequent high-temperature 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 enables the production of thinner, more robust radiation detectors with improved signal quality and extended vertical and lateral dimensions, suitable for large-area wafers, while avoiding defects and maintaining high breakdown voltage and low leakage current.
Implementation Method 1
annealing the amorphous semiconductor layer to transform at least a part of the amorphous semiconductor layer into a substantially monocrystalline semiconductor layer
Implementation Method 2
transform at least a part of the amorphous semiconductor layer into a substantially monocrystalline semiconductor layer
Data Source
AI summary
A method for forming a semiconductor device includes forming an amorphous semiconductor layer adjacent to a lightly doped region of a semiconductor wafer. The lightly doped region forms at least part of a back side of the semiconductor wafer, and the lightly doped region has a first conductivity type. The method further includes incorporating dopants into the amorphous semiconductor layer during or after forming the amorphous semiconductor layer. The method further includes annealing the amorphous semiconductor layer to transform at least a part of the amorphous semiconductor layer into a substantially monocrystalline semiconductor layer and to form a highly doped region in the monocrystalline semiconductor layer at the back side of the semiconductor wafer. The highly doped region has the first conductivity type.