III-Nitride Strain Structures for Higher Hole Mobility
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Solution Overview
Problem
Existing group-III-Nitride photonic devices based on biaxial strained heterostructures are limited by low hole conductivity due to high relative hole mass and low hole mobility in group-III Nitride materials.
Innovation Solution
Incorporating strain into photonic nitride heterostructures to upwardly move the light hole band, reducing the relative mass of holes compared to electrons, thereby enhancing hole mobility and device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If biaxial strained heterostructures are used in group-III-Nitride photonic devices, then the device structure is established, but hole conductivity remains low due to high relative hole mass and low hole mobility
Solution Approach 1:
The patent applies uniaxial strain instead of biaxial strain, changing the strain configuration parameter from two-directional to one-directional. This parameter change selectively modifies the light hole band structure while maintaining device structural feasibility, thereby improving hole conductivity without proportionally increasing complexity
Solution Approach 2:
The patent introduces strain selectively in specific regions and directions (uniaxial strain along particular crystallographic directions) rather than uniformly applying biaxial strain throughout the heterostructure. This localized strain application targets the light hole band specifically, improving hole conductivity where needed while minimizing overall structural complexity
2Speed
If strain is incorporated to move the light hole band upward and reduce hole mass, then hole mobility is enhanced, but device structure and strain management become more complex
Solution Approach 1:
The patent changes the strain parameter from biaxial to uniaxial, which selectively affects the light hole band energy and effective mass. This parameter modification achieves the desired band structure transformation that enhances hole mobility while maintaining simpler strain management compared to biaxial configurations
Solution Approach 2:
The patent applies strain locally in specific crystallographic directions to target the light hole band specifically. By concentrating strain effects where they most impact hole mobility (in the direction of hole transport), the patent achieves enhanced speed without requiring complex multi-directional strain management
3Reliability
If uniaxial strain is applied to improve hole transport, then hole mobility increases, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies uniaxial strain in a single primary direction rather than biaxial strain requiring control in two directions. This localized strain application simplifies the manufacturing precision requirements by focusing strain control on one principal axis, thereby improving hole transport properties without proportionally increasing manufacturing difficulty
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 introduction of strain significantly improves the performance of optoelectronic devices such as lasers and LEDs by reducing the threshold carrier density and enhancing hole transport properties.
Implementation Method 1
Incorporating strain into photonic nitride heterostructures to upwardly move the light hole band, reducing the relative mass of holes compared to electrons, thereby enhancing hole mobility and device performance
Data Source
AI summary
The disclosure describes the use of strain to enhance the properties of p- and n-materials so as to improve the performance of III-N electronic and optoelectronic devices. In one example, transistor devices include a channel aligned along uniaxially strained or relaxed directions of the III-nitride material in the channel. Strain is introduced using buffer layers or source and drain regions of different composition