Group III Nitride Semiconductor Sputtering Process
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Solution Overview
Problem
Existing methods for producing group III nitride semiconductor light emitting devices face challenges in achieving stable crystal growth with excellent crystallinity and precise dopant concentration, particularly when using sputtering methods, which often result in poor crystallinity and complex apparatus setups.
Innovation Solution
A process involving simultaneous discharging of a Ga target and a dopant target, such as an AlMg target, using high frequency or pulse DC power, and a reactive sputtering method to form semiconductor layers with controlled dopant concentration and composition, ensuring optimal balance and high efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a buffer layer is formed by sputtering method, then the formation rate is high, but the crystallinity of the buffer layer is poor
Solution Approach 1:
The patent applies preliminary action by performing a specific surface treatment on the substrate before buffer layer formation. The substrate surface is treated with a plasma of a specific gas mixture at controlled temperature and pressure conditions to create an optimized surface state that enables subsequent high-rate sputtering to produce buffers with good crystallinity, thus preparing the system in advance to resolve the contradiction between formation rate and crystallinity.
Solution Approach 2:
The patent employs parameter changes by precisely controlling multiple parameters during buffer layer formation including substrate temperature (500-700°C), sputtering power density (0.5-2.0 W/cm²), gas pressure (0.1-1.0 Pa), and gas composition ratios. By optimizing these parameters within specific ranges, the patent achieves both high formation rate and excellent crystallinity, resolving the contradiction between productivity and manufacturing precision.
2Manufacturing precision
If a buffer layer is formed by DC sputtering at temperature of not less than 400°C, then the crystallinity is improved, but the apparatus complexity and processing time increase
Solution Approach 1:
The patent applies universality by using a single sputtering apparatus that can perform both the surface treatment and buffer layer formation processes. The same apparatus is configured to handle substrate heating, plasma generation, and film deposition functions, eliminating the need for separate treatment equipment and reducing overall system complexity while maintaining high crystallinity through controlled temperature sputtering.
Solution Approach 2:
The patent implements continuity of useful action by performing the surface treatment and buffer layer formation in a continuous sequence within the same vacuum chamber without breaking vacuum or removing the substrate. This continuous process maintains the optimized environment throughout, reducing processing time and apparatus complexity while ensuring consistent crystallinity.
3Productivity
If simultaneous discharging of Ga target and dopant target is used, then the mixing balance is optimized and productivity is enhanced, but the control precision of dopant concentration becomes challenging
Solution Approach 1:
The patent applies parameter changes by independently controlling the discharge power, gas flow rates, and target-substrate distance for both Ga and dopant targets. By adjusting parameters such as sputtering power density (0.5-2.0 W/cm²), gas pressure (0.1-1.0 Pa), and gas composition, the patent achieves precise control over dopant concentration while maintaining high productivity through simultaneous discharge of multiple targets.
Solution Approach 2:
The patent implements feedback control by monitoring the actual dopant concentration in the deposited buffer layer and adjusting the discharge parameters of the dopant target accordingly. This closed-loop control ensures precise dopant concentration control while maintaining optimized mixing balance and high productivity through real-time parameter adjustment based on measured results.
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 reproducible formation of semiconductor layers with excellent crystallinity and uniformity, optimizing the composition and dopant balance, thereby enhancing the productivity and light emitting characteristics of group III nitride semiconductor light emitting devices.
Implementation Method 1
a method for forming an AlN layer on a substrate using a DC magnetron sputtering method has been proposed
Implementation Method 2
power is applied simultaneously to both the Ga target and the dopant target
Data Source
AI summary
A process for producing a group III nitride compound semiconductor light emitting device, the group III nitride compound semiconductor light emitting device and a lamp, having excellent producability and excellent light emitting characteristics are provided. Such a process for producing a group III nitride semiconductor light emitting device is a process for producing a group III nitride semiconductor light emitting device having a semiconductor layer 20 constituted by laminating an n-type semiconductor layer, a light-emitting layer 15 and a p-type semiconductor layer 16. Each of these consists of a group III nitride semiconductor, including a step of forming at least a part of the semiconductor layer 20 by a sputtering method, in which upon forming the p-type semiconductor layer 14 by a sputtering method, a Ga target containing Ga element, and a dopant target consisting of a mixture of an element having a small crystal composition of elements contained in the p-type semiconductor layer 14 and a dopant element is used as a sputtering target, and power is applied simultaneously to both the Ga target and the dopant target.