Semipolar Nitride Film Defect Reduction via Lateral Growth
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Solution Overview
Problem
Current nitride semiconductor devices grown in the c-plane orientation suffer from detrimental polarization effects, leading to decreased radiative recombination efficiency and fabrication challenges for green LEDs and LDs, due to high defect densities and strain-induced piezoelectric polarization in heterostructures.
Innovation Solution
A lateral growth method is employed to reduce defect density in semipolar nitride films by selecting a suitable semipolar nitride plane and composition, applying a selective growth process, and using techniques like lateral epitaxial overgrowth (LEO), sidewall lateral epitaxial overgrowth (SLEO), cantilever epitaxy, or nanomasking to nucleate nitride material on specific areas, allowing it to grow laterally and coalesce or remain uncoalesced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If c-plane orientation nitride films are grown using conventional heteroepitaxial methods, then device fabrication can proceed with standard processes, but high defect densities and strain-induced piezoelectric polarization occur leading to decreased radiative recombination efficiency
Solution Approach 1:
The patent transitions from conventional c-plane growth to semipolar plane growth, changing the crystallographic orientation dimension. This dimensional change in growth plane selection fundamentally alters the polarization characteristics and defect propagation behavior, enabling reduced piezoelectric polarization and improved radiative recombination efficiency while maintaining manufacturability
Solution Approach 2:
The patent changes the growth parameters by selecting semipolar orientations ({1011}, {1122}, etc.) instead of conventional c-plane ({0001}). This parameter change in crystallographic orientation modifies the physical properties including polarization effects and defect density, directly addressing the contradiction between reliability and manufacturing precision
2Manufacturing precision
If lateral growth methods are employed to reduce defect density in semipolar nitride films, then defect density decreases improving device performance, but the growth process complexity increases
Solution Approach 1:
The lateral growth process is segmented into distinct stages: initial nucleation on patterned substrates, lateral overgrowth across the surface, and controlled coalescence. This segmentation allows systematic control of defect reduction while managing process complexity through structured, step-by-step implementation
Solution Approach 2:
The method employs preliminary patterning of the substrate surface before growth, creating defined nucleation sites that guide subsequent lateral growth. This preliminary action establishes a controlled template that simplifies the overall process by pre-determining growth pathways and reducing the complexity of achieving uniform defect reduction
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 approach results in semipolar nitride films with reduced defect density, potentially leading to higher performance optoelectronic devices by mitigating polarization effects and strain-induced issues, enabling the growth of high-quality semipolar nitride films for subsequent device fabrication.
Implementation Method 1
A lateral growth method is employed to reduce defect density in semipolar nitride films by selecting a suitable semipolar nitride plane and composition, applying a selective growth process, and using techniques like lateral epitaxial overgrowth (LEO), sidewall lateral epitaxial overgrowth (SLEO), cantilever epitaxy, or nanomasking to nucleate nitride material on specific areas
Data Source
AI summary
A lateral growth method for defect reduction of semipolar nitride films. The process steps include selecting a semipolar nitride plane and composition, selecting a suitable substrate for growth of the semipolar nitride plane and composition, and applying a selective growth process in which the semipolar nitride nucleates on some areas of the substrate at the exclusion of other areas of the substrate, wherein the selective growth process includes lateral growth of nitride material by a lateral epitaxial overgrowth (LEO), sidewall lateral epitaxial overgrowth (SLEO), cantilever epitaxy or nanomasking.