Nitride Semiconductor Crystal Growth on Nonpolar Planes
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Solution Overview
Problem
Conventional nitride semiconductor crystal growth methods on nonpolar planes face challenges in achieving high-quality crystals with low dislocation density and good surface morphology, leading to inadequate optical characteristics and luminous efficiency.
Innovation Solution
A nitride semiconductor crystal growth method using a nonpolar plane as the growth substrate, where an inactive gas is used to control the atmosphere and prevent nitrogen loss, and the initial nitride semiconductor layer is optimized for improved crystallinity, resulting in low dislocation density and enhanced optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional crystal growth methods are used on nonpolar planes, then growth can be achieved, but the dislocation density remains high and surface morphology is poor
Solution Approach 1:
The patent applies parameter changes by systematically optimizing growth temperature (900-1100°C), pressure (10-100 Torr), and V/III ratio (5-20) to achieve low dislocation density and high crystal quality on nonpolar planes, resolving the contradiction between achievable growth and crystal quality
Solution Approach 2:
The patent uses an inert ammonia atmosphere during crystal growth to prevent nitrogen loss and maintain stoichiometry, which reduces dislocation density and improves crystal quality, directly addressing the reliability issue
2Manufacturing precision
If conventional crystal growth methods are used on nonpolar planes, then growth can be achieved, but surface morphology is inadequate
Solution Approach 1:
The patent optimizes growth parameters including temperature (900-1100°C), pressure (10-100 Torr), and V/III ratio (5-20) to achieve atomically flat surfaces with RMS roughness less than 1 nm, resolving the contradiction between achievable growth and surface morphology
Solution Approach 2:
The patent employs continuous monitoring and control of growth conditions throughout the epitaxial process to maintain stable surface morphology, ensuring consistent high-quality crystal growth without interruptions that would degrade surface quality
3Manufacturing precision
If conventional crystal growth methods are used on nonpolar planes, then growth can be achieved, but optical characteristics are insufficient
Solution Approach 1:
The patent optimizes growth temperature (900-1100°C) and pressure (10-100 Torr) to achieve low dislocation density and high crystal quality, which directly improves optical characteristics including light emission intensity and quality
Solution Approach 2:
The patent uses precise control of gas flow rates and pressure conditions during epitaxial growth to maintain optimal atmospheric conditions, which enhances crystal quality and resulting optical properties
4Manufacturing precision
If conventional crystal growth methods are used on nonpolar planes, then growth can be achieved, but luminous efficiency is low
Solution Approach 1:
The patent optimizes growth temperature (900-1100°C), pressure (10-100 Torr), and V/III ratio (5-20) to achieve high crystal quality with low dislocation density, which directly improves luminous efficiency by reducing non-radiative recombination centers
Solution Approach 2:
The patent maintains an inert ammonia atmosphere during growth to prevent nitrogen loss and maintain stoichiometry, reducing defects that would otherwise reduce luminous efficiency
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 method enables the growth of high-quality nitride semiconductors with low dislocation density and good surface morphology, leading to improved luminous efficiency and optical characteristics suitable for light-emitting elements.
Implementation Method 1
growing a crystal of a nitride semiconductor on a principal nitride plane of a base at least one principal plane of which is a nonpolar nitride plane
Data Source
Figure 1(A)~1(B)
Figure 2(A)
Figure 2(B)
AI summary
In growing a crystal of a nitride semiconductor on a nitride base which uses a nonpolar plane such as an m-plane, gases which do not have etching effect on nitrides are mainly used as constituent gases of a main flow (atmosphere to which a principal nitride plane of the base is exposed) during a heating step in a relatively high temperature region before nitride semiconductor layers are grown and constituent gases of a main flow during a period lasting until growth of a first and second nitride semiconductor layers is completed. Also, Si source material is not supplied in an initial growth stage of the nitride semiconductor layers. This reduces removal of nitrogen atoms from near a nitride surface of the epitaxial base and thereby reduces introduction of defects into epitaxial films, enabling epitaxial growth with surface morphology characterized by excellent flatness.