Stress Control Structure for UV LED Heterostructure Defect Reduction
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Solution Overview
Problem
The performance and reliability of ultraviolet (UV) LEDs based on group III nitride semiconductor layers are hindered by high dislocation density and crack issues, which existing substrate patterning methods fail to effectively address, especially in large-scale production, and do not consistently translate to improved device efficiency and longevity.
Innovation Solution
A stress control structure, including piezoelectric materials and Joule heating components, is introduced to exert controlled stresses on semiconductor heterostructures, allowing for wavelength tuning and device testing, with the stress control structure being implemented as a substrate or layer within the device to minimize defects and enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substrate patterning approaches are used to minimize dislocation density and cracks, then device reliability is improved, but manufacturing cost increases and productivity decreases
Solution Approach 1:
The patent extracts the stress control function from the substrate itself and implements it through a separate, removable stress control layer. This layer can be applied after epitaxial growth and removed afterward, separating the stress management process from the substrate manufacturing process, thereby improving both reliability and productivity
Solution Approach 2:
The patent introduces a stress control layer as an intermediary between the substrate and the semiconductor layers. This intermediary layer provides controlled stress to minimize dislocation density and cracks during growth, then can be removed to leave a high-quality device structure without requiring complex substrate patterning
2Manufacturing precision
If substrate patterning is used to improve epitaxial layer quality, then device performance is improved, but manufacturing cost increases
Solution Approach 1:
The stress control layer acts as a temporary, disposable element that is applied during the growth process to improve layer quality, then removed before final device assembly. This inexpensive temporary structure enables high-quality epitaxial growth without requiring expensive permanent substrate modifications
Solution Approach 2:
The stress control layer is applied before epitaxial growth to pre-condition the substrate surface and stress state, ensuring optimal conditions for high-quality layer formation. This preliminary action simplifies the overall manufacturing process by preventing defects rather than requiring complex post-processing
3Adaptability or versatility
If stress control structure is added to tune emission wavelength, then device functionality is improved, but device complexity increases
Solution Approach 1:
The stress control layer serves multiple functions: it provides controlled stress to minimize dislocations, enables wavelength tuning through stress adjustment, and can be applied to various device types. This multi-functionality reduces overall device complexity by consolidating multiple requirements into a single element
Solution Approach 2:
The patent utilizes parameter changes in the stress control layer (such as thickness, material composition, or applied stress magnitude) to tune the emission wavelength. This provides a simple, continuous adjustment mechanism for wavelength control without requiring complex structural modifications to the active regions
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 stress control structure improves device performance and operational lifetime by reducing defects and allowing for precise tuning of emission/absorption wavelengths, enabling effective testing and evaluation of semiconductor layers under various stress conditions.
Implementation Method 1
The stress controlling substrate can include a piezoelectric material, such as LiNbO3, LiTaO3, PZT, quartz, and/or the like
Implementation Method 2
The stress controlling substrate can include a plurality of composite domains having temperature activated materials that are configured for Joule heating
Data Source
AI summary
An optoelectronic device with at least one stress controlling structure and method of testing the device is disclosed. The optoelectronic device includes a stress controlling structure formed adjacent to a semiconductor heterostructure. The optoelectronic device can further include a stress inducing component that is configured to induce a change in stress within the stress controlling structure. The stress inducing component can induce a number of different stresses during a test of the optoelectronic device. A strain evaluator can evaluate the stresses within the semiconductor heterostructure as a function of a strain generated in the stress controlling structure.