Graphite Substrate Nitride Semiconductor Light Emitting Device
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nitride-based LEDs are expensive due to high production costs on monocrystalline substrates and have limited flexibility, while organic EL devices have low heat resistance and short lifetimes with lower luminescent efficiency.
Innovation Solution
A semiconductor substrate with a graphite substrate and nitride semiconductor layers, including a sintered polymer and HfN or ZrN layers, allowing for low-cost manufacturing, high luminescent efficiency, and flexibility, enabling the creation of a bendable light emitting device with improved heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitride-based LEDs are mass-produced on monocrystalline substrates using MOCVD method, then high luminescent efficiency and long lifetime are achieved, but production cost increases and mass productivity decreases
Solution Approach 1:
The patent changes the substrate material parameter from expensive monocrystalline substrates to inexpensive polyimide substrates, and changes the deposition method parameter from MOCVD to sputtering method, thereby achieving cost reduction while maintaining device performance and enabling higher productivity
Solution Approach 2:
The patent replaces expensive monocrystalline substrates with inexpensive polyimide substrates that can be easily disposed of after use, significantly reducing production costs while maintaining the required device lifetime through optimized semiconductor layer structures
2Reliability
If nitride-based LEDs are produced on monocrystalline substrates, then high luminescent efficiency is achieved, but device price increases
Solution Approach 1:
The patent changes the substrate material parameter from expensive monocrystalline substrates to inexpensive polyimide substrates, and optimizes the semiconductor layer composition and structure parameters to maintain high luminescent efficiency while dramatically reducing manufacturing costs
Solution Approach 2:
The patent uses inexpensive polyimide substrates that can be easily disposed of after device fabrication, eliminating the need for expensive reusable monocrystalline substrates and thereby reducing overall manufacturing costs while maintaining device performance
3Ease of manufacture
If organic EL devices use plastic or glass substrates, then device price decreases and surface light source application is enabled, but heat resistance decreases and lifetime shortens
Solution Approach 1:
The patent uses a composite structure combining polyimide substrate with nitride semiconductor layers, where the polyimide provides flexibility and low cost while the nitride semiconductor layers provide high heat resistance and long lifetime, achieving synergistic effects that overcome the limitations of pure organic EL devices
Solution Approach 2:
The patent introduces a buffer layer as an intermediary between the polyimide substrate and the nitride semiconductor layer, which mediates the thermal and mechanical properties to protect the organic substrate from high temperatures during semiconductor layer formation while enabling the use of inexpensive plastic substrates
4Ease of operation
If graphite substrate thickness is reduced to 100 μm or less, then flexibility with respect to external force is improved, but structural strength may decrease
Solution Approach 1:
The patent uses a composite structure where the thin graphite substrate (100 μm or less) is combined with multiple semiconductor layers and buffer layers that provide structural reinforcement, enabling the substrate to maintain both high flexibility for bending applications and sufficient structural strength for device integrity
Solution Approach 2:
The patent optimizes the local quality of the graphite substrate by controlling its thickness distribution and combining it with strategically placed semiconductor layers and buffer layers that provide localized structural support where needed while maintaining overall flexibility in other 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 solution results in a low-cost, long-lifetime, high-efficiency light emitting device that can be bent, offering a wider range of applications with enhanced electrical and optical characteristics.
Implementation Method 1
the graphite substrate includes a sintered polymer
Implementation Method 2
Nitride-based LEDs using p-n junction of AlN, GaN, InN which are nitrides of the Group XIII and the mixed crystal phase thereof
Data Source
Figure 1~2
Figure 3~4
Figure 5~6(b)
AI summary
To provide a semiconductor substrate, a semiconductor device, a light emitting device and an electronic device which have a low price, a long lifetime, and a high luminescent efficiency, and moreover are capable of being bent. A graphite substrate having heat resistance and having flexibility with respect to external force, and a first semiconductor layer, provided on the graphite substrate, which is made of a nitride of the Group XIII are included, and a method such as pulse sputter deposition can be used in forming the first semiconductor layer on the graphite substrate, to thereby allow inexpensive manufacture to be possible. In addition, since the nitride of the Group XIII is an inorganic substance, it has a long lifetime, and thus a high luminescent efficiency can be obtained. Moreover, since the graphite substrate has flexibility with respect to external force, it can also be bent.