GaN Semiconductor Layer Sputtering for Crystallinity
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Solution Overview
Problem
Existing methods for manufacturing group-III nitride compound semiconductor light-emitting devices face challenges in achieving high crystallinity and productivity due to large lattice mismatches between substrates and grown crystals, leading to difficulties in forming stable and uniform crystal films.
Innovation Solution
A method involving a sputtering process with specific conditions, including a lower degree of vacuum, controlled internal pressure, substrate temperature range of 500 to 800°C, and a bias application, is used to form a semiconductor layer with a buffer layer of columnar crystals, enhancing crystallinity and deposition rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a group-III nitride semiconductor crystal is grown on a sapphire or SiC substrate using conventional MOCVD method with a low temperature buffer layer, then the crystal can be formed on the substrate, but the crystallinity is poor due to large lattice mismatch
Solution Approach 1:
The invention changes the fundamental parameters of the deposition process by using sputtering instead of MOCVD, operating at lower pressure (0.3-1.0 Pa) and lower substrate temperature (room temperature to 500°C). This parameter change enables direct growth of high-quality GaN crystals on sapphire substrates without requiring a low temperature buffer layer, thereby improving crystallinity while simplifying the manufacturing process
Solution Approach 2:
The invention replaces the chemical vapor deposition mechanism (MOCVD) with a physical sputtering mechanism. By using ion bombardment and physical deposition rather than chemical reactions, the process achieves better crystallinity and eliminates the need for complex buffer layer structures, resolving the contradiction between manufacturing ease and crystal quality
2Productivity
If the deposition rate is increased to improve productivity, then the manufacturing time is reduced, but the crystallinity and uniformity of the semiconductor layer deteriorate
Solution Approach 1:
The invention introduces dynamic control of deposition parameters during the sputtering process. By dynamically adjusting the radio frequency power, gas flow rates, and substrate temperature during deposition, the process maintains optimal crystallinity even at higher deposition rates, resolving the contradiction between productivity and crystal quality
Solution Approach 2:
The invention implements feedback control by monitoring deposition rate and crystal quality in real-time, then adjusting sputtering parameters accordingly. This feedback mechanism enables the process to maintain high crystallinity while operating at optimized deposition rates for improved productivity
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 allows for the stable formation of uniform group-III nitride compound semiconductor layers with high crystallinity and productivity, improving emission characteristics and reducing manufacturing time.
Implementation Method 1
a step of forming on a substrate a semiconductor layer made of a group-III nitride compound semiconductor including Ga as a group-III element using a sputtering method
Implementation Method 2
when the semiconductor layer is formed, a bias is applied to the substrate
Data Source
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AI summary
The present invention provides a group-III nitride compound semiconductor light-emitting device having high productivity and good emission characteristics, a method of manufacturing a group-III nitride compound semiconductor light-emitting device, and a lamp. A method of manufacturing a group-III nitride compound semiconductor light-emitting device includes a step of forming on a substrate 11 a semiconductor layer made of a group-III nitride compound semiconductor including Ga as a group-III element using a sputtering method. The substrate 11 and a sputtering target are arranged so as to face each other, and a gap between the substrate 11 and the sputtering target is in the range of 20 to 100 mm. In addition, when the semiconductor layer is formed by the sputtering method, a bias of more than 0.1 W/cm2 is applied to the substrate 11. Further, when the semiconductor layer is formed, nitrogen and argon are supplied into a chamber used for sputtering.