Photonic Device Current Confinement Layer Doping
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Solution Overview
Problem
Conventional photonic devices suffer from unwanted conductive currents that cross the interface between the device and substrate, leading to increased noise and reduced performance, particularly due to dark current and sidewall leakage, which negatively impact signal-to-noise ratio.
Innovation Solution
A current confinement layer is introduced, doped in a pattern with varying concentrations of dopants to confine conductive currents within specific regions, reducing dark current and leakage, and comprising materials like Si, GeSi, Ge, or III-V materials grown using epitaxial processes such as RPCVD, UHV/CVD, or MOCVD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the substrate layers are uniformly and heavily doped to reduce series resistance and improve electrical connection, then electrical connection is improved, but unwanted conductive currents cross the entire interface causing increased noise and reduced device performance
Solution Approach 1:
The patent applies local quality by creating a current confinement layer with spatially varying doping concentrations. The layer has a first region with higher doping concentration and a second region with lower doping concentration, allowing different parts of the same layer to perform different functions: the first region provides low resistance for useful current, while the second region acts as a barrier to unwanted leakage currents.
Solution Approach 2:
The current confinement layer is segmented into multiple regions with different doping concentrations. This segmentation allows the layer to simultaneously provide electrical connection in some regions while blocking unwanted currents in other regions, resolving the contradiction between maintaining good electrical connection and preventing harmful current leakage.
2Ease of manufacture
If the photonic device has large sidewall leakage current, then device fabrication is simplified, but device performance is hampered due to increased noise
Solution Approach 1:
The current confinement layer acts as an intermediary structure between the substrate and the photonic device. It mediates the conflicting requirements by providing a controlled path for useful current while blocking unwanted sidewall leakage currents, thereby improving device performance without significantly complicating the fabrication process.
3Reliability
If uniform heavy doping is used to improve electrical connection, then series resistance is reduced, but signal-to-noise ratio is reduced due to increased dark current
Solution Approach 1:
By implementing local quality through non-uniform doping in the current confinement layer, the patent achieves low series resistance in the first region while maintaining high signal-to-noise ratio through the second region with lower doping that suppresses dark current and unwanted leakage.
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 current confinement layer effectively reduces dark current and leakage, enhancing the signal-to-noise ratio without compromising photodiode or laser device responsivity, thereby improving the overall performance of photonic devices.
Implementation Method 1
a current confinement layer disposed on the substrate, the current confinement layer being doped in a pattern and configured to reduce dark current in the device
Implementation Method 2
the current confinement layer being doped in a pattern with varying concentrations of dopants
Implementation Method 3
an absorption layer disposed on the current confinement layer
Implementation Method 4
comprising materials like Si, GeSi, Ge, or III-V materials grown using epitaxial processes such as RPCVD, UHV/CVD, or MOCVD
Data Source
AI summary
Various embodiments of a photonic device and fabrication method thereof are provided. In one aspect, a device includes a substrate, a current confinement layer disposed on the substrate, an absorption layer disposed in the current confinement layer, and an electrical contact layer disposed on the absorption layer. The current confinement layer is doped in a pattern and configured to reduce dark current in the device. The photonic device may be a photodiode or a laser.