Semiconductor Device Deep Multiplication Region NIR Detection
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Solution Overview
Problem
Avalanche photodiodes have a low photo detection probability for near-infrared (NIR) light due to their shallow junction depth compared to the absorption depth of NIR electromagnetic waves, limiting their efficiency in detecting long-wavelength light.
Innovation Solution
A semiconductor device with a deep multiplication region between a buried doped layer and a doped well is introduced, where the doped concentration of the doped well decreases in depth, enhancing the collection of photo-generated carriers and increasing the avalanche probability for electrons, thus improving photo detection probability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional APD structure with shallow junction depth is used, then the device structure is simple and easy to manufacture, but the photo detection probability for NIR light is low
Solution Approach 1:
The patent extends the detection depth from shallow junction (conventional 1D surface detection) to deep multiplication region (extended into the substrate depth dimension). By creating a deep P-N junction that penetrates into the substrate, the device can detect photons absorbed at greater depths, effectively utilizing the third dimension (depth) to overcome the limitation of shallow junction detection.
Solution Approach 2:
The patent creates a multiplication region with locally optimized properties: high electric field strength, specific doping concentration gradient, and appropriate depth positioning. This localized region with enhanced carrier multiplication capability (avalanche effect) is positioned where it can effectively collect carriers generated by NIR photons, providing localized high-performance detection without requiring the entire device structure to be complex.
2Reliability
If the junction depth is increased to match the absorption depth of NIR light, then the photo detection probability improves, but the device complexity increases
Solution Approach 1:
The patent optimizes key parameters including: doping concentration gradient (decreasing from surface to depth), multiplication region depth (positioned to match NIR absorption profile), and electric field distribution (peaked in the multiplication region). By carefully controlling these parameters, the device achieves deep NIR detection capability while maintaining a relatively simple single-P-N junction structure without requiring multiple complex layers or components.
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 deep multiplication region and decreasing doped concentration profile significantly enhance the collection of NIR light-generated carriers, doubling the avalanche probability for electrons and significantly increasing the photo detection probability for long-wavelength electromagnetic waves.
Implementation Method 1
photo detection probability... collection of photo generated carriers induced by an electromagnetic wave
Implementation Method 2
increasing the avalanche probability for electrons... doubling the avalanche probability for electrons
Data Source
AI summary
A semiconductor device includes a substrate, a buried doped layer, a first doped well, a multiplication region and a first contact doped region. The substrate has a first doping type, wherein the substrate includes a surface. The buried doped layer is in the substrate and exposed from the surface of the substrate, wherein the buried doped layer has a second doping type opposite to the first doping type. The first doped well is over the buried doped layer, wherein the first doped well has the first doping type. The multiplication region is proximal to an interface between the buried doped layer and the first doped well. The first contact doped region is over the first doped well, wherein the first contact doped region has the first doping type and a doped concentration higher than a doped concentration of the first doped well.