III-N Bulk Crystal Growth Rate Control via Real-Time Feedback
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Solution Overview
Problem
Current methods for producing III-N bulk crystals and substrates face challenges such as low crystal quality, high production costs, and difficulty in achieving homogeneous defect density due to high nitrogen vapor pressure and complex substrate separation processes.
Innovation Solution
A process involving vapor phase epitaxy with real-time measurement and active control of growth rate to maintain a constant growth rate, ensuring excellent crystal quality and homogenous distribution in III-N bulk crystals and substrates, using methods like weighing, ultrasonic wave reflection, or shadow casting to monitor and adjust growth rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bulk growth technology under high pressure is used to produce III-N substrates, then crystal quality is improved, but production time increases and costs increase
Solution Approach 1:
The patent changes the pressure parameter from high pressure to atmospheric pressure, and changes the growth method from conventional bulk growth to vapor phase epitaxy with real-time growth rate control. This allows achieving good crystal quality without the extended production times and high costs associated with high pressure bulk growth methods
2Reliability
If conventional bulk growth technology under high pressure is used to produce III-N substrates, then crystal quality is improved, but manufacturing costs increase
Solution Approach 1:
The patent changes the pressure parameter from high pressure to atmospheric pressure, making the manufacturing process less costly. The use of vapor phase epitaxy with real-time growth rate control at atmospheric pressure reduces equipment requirements and operational costs while maintaining acceptable crystal quality
3Device complexity
If growth rate is not controlled in real-time during vapor phase epitaxy, then process complexity is reduced, but crystal quality and homogeneity deteriorate
Solution Approach 1:
The patent implements real-time measurement and active control of the growth rate during vapor phase epitaxy. This feedback mechanism ensures homogeneous distribution of crystal quality and consistent manufacturing precision, addressing the trade-off between process complexity and crystal quality
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 process achieves III-N bulk crystals and substrates with unique crystal quality and homogenous distribution, enabling the production of high-quality free-standing substrates suitable for optoelectronic devices with improved efficiency and reduced costs.
Implementation Method 1
the III-N bulk crystal is grown by means of vapor phase epitaxy on a substrate or a template
Implementation Method 2
grown by means of vapor phase epitaxy
Implementation Method 3
measuring or determining the growth rate by one or more of the following methods: weighing, determining a duration or running time of an ultrasonic wave which is reflected from the growth surface
Implementation Method 4
determining a crystal shadow obtained by illumination, for example by sideward illumination of the growing crystal and detecting the moving shadow behind the growing crystal
Implementation Method 5
irradiating the GaN-deposited sapphire substrate with a laser, with the result that the GaN layer is locally thermally decomposed at the interface with the sapphire substrate, and thereby lifting off
Data Source
AI summary
Embodiments of the invention relate to a process for producing a III-N bulk crystal, wherein III denotes at least one element selected from group III of the periodic system, selected from Al, Ga and In, wherein the III-N bulk crystal is grown by vapor phase epitaxy on a substrate, and wherein the growth rate is measured in real-time. By actively measuring and controlling the growth rate in situ, i.e. during the epitaxial growth, the actual growth rate can be maintained essentially constant. In this manner, III-N bulk crystals and individualized III-N single crystal substrates separated therefrom, which respectively have excellent crystal quality both in the growth direction and in the growth plane perpendicular thereto, can be obtained.