Nitride Semiconductor Device with Selective Side Surface Growth
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Solution Overview
Problem
Nitride semiconductor devices, particularly light emitting diodes and semiconductor lasers, face challenges in reducing the resistance of the p-type contact layer and contact resistance between the p-type layer and the electrode, leading to high operating voltage and limited efficiency and reliability.
Innovation Solution
A nitride semiconductor device is developed with a second nitride semiconductor layer selectively grown on the side surfaces of convex portions of a first nitride semiconductor layer, using an organic nitride material as a nitrogen source, which improves p-type dopant activation and reduces resistance, eliminating the need for patterning the p-type layer into a ridge shape and enhancing current confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat treatment is carried out in nitrogen atmosphere to obtain a p-type semiconductor layer, then p-type dopant activation is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent extracts the heat treatment step from the manufacturing process by using a nitrogen source material that provides nitrogen during film formation, eliminating the need for separate heat treatment in nitrogen atmosphere. This resolves the contradiction by removing the complex manufacturing step while maintaining p-type dopant activation through in-situ nitrogen supply during deposition.
Solution Approach 2:
The patent applies preliminary action by incorporating nitrogen into the film during the deposition process itself, rather than requiring subsequent heat treatment. The nitrogen source material is added in advance to the deposition process, allowing nitrogen to be integrated into the crystal structure during film formation, thereby activating p-type dopants without additional processing steps.
2Reliability
If the p-type contact layer resistance is reduced through conventional methods, then contact resistance decreases, but the process becomes more complex and less reliable
Solution Approach 1:
The patent changes the chemical composition parameter by introducing a nitrogen source material into the deposition process. This parameter change enables direct nitrogen incorporation during film formation, achieving low contact resistance through controlled nitrogen content in the p-type contact layer without requiring complex post-deposition processing or multiple fabrication steps.
3Ease of operation
If dry etching is used to form ridge waveguide structure, then current confinement is improved, but manufacturing precision and device reliability deteriorate
Solution Approach 1:
The patent replaces the mechanical dry etching process with a deposition-based approach. Instead of removing material to form ridges, the invention uses selective deposition of nitride semiconductor layers to create the ridge waveguide structure. This substitution eliminates the precision and reliability issues associated with dry etching while achieving effective current confinement through controlled film thickness and composition gradients.
Solution Approach 2:
The patent employs parameter changes in the deposition process, specifically varying the nitrogen source material addition and film composition during deposition, to create the ridge structure. This approach provides superior thickness control and interface quality compared to etching, as deposition allows atomic-level precision in layer formation and composition control without the damage and variability introduced by mechanical or plasma etching.
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 configuration significantly reduces the series resistance and operating voltage of the device, improves light emitting efficiency, and enhances the reliability and yield of nitride semiconductor devices by providing a current confining structure without the need for complex patterning processes.
Implementation Method 1
a second nitride semiconductor layer selectively grown on the side surfaces of the one or more convex portions
Data Source
AI summary
A nitride semiconductor device includes: a substrate having a principal surface; a first nitride semiconductor layer formed on the principal surface of the substrate and includes one or more convex portions whose side surfaces are vertical to the principal surface; and a second nitride semiconductor layer selectively grown on the side surfaces of the one or more convex portions of the first nitride semiconductor layer.