Germanium Photodetector Passive Cap for Oxygen and Growth Control
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Solution Overview
Problem
Existing semiconductor devices using silicon dioxide as a passive cap for germanium photodetectors suffer from oxygen contamination, leading to leakage current and performance degradation, while silicon nitride lacks sufficient growth suppression, affecting throughput during co-flow etch processes.
Innovation Solution
Employing a passive cap comprising silicon nitride and hydrogen to prevent oxygen contamination and enhance growth suppression, allowing for a controlled co-flow etch process that maintains throughput and prevents electrical shorting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If silicon dioxide is used as a passive cap for germanium photodetectors, then oxygen contamination is prevented, but leakage current increases and device performance degrades
Solution Approach 1:
The patent employs a composite passive cap structure comprising silicon nitride and hydrogen. The silicon nitride layer provides oxygen barrier properties to prevent contamination, while the hydrogen component suppresses semiconductor layer growth on the passive cap surface. This composite approach simultaneously addresses both the oxygen contamination issue and the leakage current problem without compromising device performance.
2Object-affected harmful factors
If silicon nitride is used as a passive cap, then oxygen contamination is reduced, but growth suppression is insufficient affecting throughput
Solution Approach 1:
The passive cap combines silicon nitride with hydrogen to create a composite material that exhibits both oxygen barrier properties and enhanced growth suppression. The hydrogen component specifically addresses the insufficient growth suppression of pure silicon nitride, enabling better control during co-flow etch processes and improving manufacturing throughput.
Solution Approach 2:
The invention modifies the chemical composition parameters of the passive cap by incorporating hydrogen into the silicon nitride matrix. This parameter change transforms the passive cap from a simple oxygen barrier into a dual-functional layer that also provides growth suppression, thereby improving etch process control and productivity.
3Object-affected harmful factors
If silicon nitride is used as a passive cap, then oxygen contamination is minimized, but electrical shorting occurs due to insufficient growth suppression
Solution Approach 1:
The composite passive cap of silicon nitride and hydrogen provides dual functionality: the silicon nitride component minimizes oxygen contamination while the hydrogen component provides sufficient growth suppression to prevent electrical shorting. This composite structure ensures both reliability aspects are addressed simultaneously.
Solution Approach 2:
Hydrogen acts as an intermediary substance within the passive cap structure, mediating between the silicon nitride matrix and the semiconductor layer. It provides growth suppression that prevents excessive semiconductor material deposition on the passive cap, thereby preventing electrical shorting while allowing the silicon nitride to perform its oxygen barrier function.
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 silicon nitride-hydrogen passive cap reduces leakage current and improves semiconductor device performance by minimizing oxygen contamination and controlling semiconductor layer growth, ensuring efficient manufacturing without electrical shorting.
Implementation Method 1
Employing a passive cap comprising silicon nitride and hydrogen to prevent oxygen contamination
Implementation Method 2
enhance growth suppression, allowing for a controlled co-flow etch process
Data Source
AI summary
In some embodiments, the present disclosure relates to a semiconductor device, including a substrate including a first semiconductor material and a semiconductor layer extending into an upper surface of the substrate and including a second semiconductor material with a different band gap than the first semiconductor material. The semiconductor device also includes a passive cap including a first dielectric material and disposed along the upper surface of the substrate and on opposite sides of the semiconductor layer, and a photodetector in the semiconductor layer. The first dielectric material includes silicon nitride.