VCSEL Nitride Reflector Growth to Reduce AlInN Dislocations
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Solution Overview
Problem
The occurrence of dislocations in semiconductor layers of a nitride semiconductor multilayer film reflector used in vertical cavity surface emitting laser elements is a challenge, particularly in AlInN layers, leading to optical loss and reduced efficiency.
Innovation Solution
A manufacturing method involving alternating growth of first semiconductor layers containing aluminum and indium with higher indium composition and second semiconductor layers of gallium nitride, with controlled growth conditions to reduce dislocations, is employed to form a nitride semiconductor multilayer film reflector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AlInN layers are used as first semiconductor layers in the nitride semiconductor multilayer film reflector, then the reflector can be formed with the required structure, but dislocations occur in the AlInN layers
Solution Approach 1:
The first semiconductor layer containing aluminum and indium is divided into a first layer and a second layer with different indium composition ratios. This segmentation allows the indium-rich second layer to be grown on a less strained first layer, reducing dislocation formation while maintaining the required optical properties of the reflector structure.
Solution Approach 2:
Different regions of the first semiconductor layer are given different indium composition ratios - the first layer has a lower indium composition while the second layer has a higher indium composition. This local quality variation optimizes both the structural integrity and optical performance of the reflector by placing high-indium regions only where needed for optical functionality.
2Reliability
If dislocations occur in the semiconductor layers of the reflector, then the reflector structure is formed, but optical loss increases and external quantum efficiency decreases
Solution Approach 1:
By segmenting the first semiconductor layer into two layers with different indium compositions, the patent reduces dislocation density in the AlInN layers. This segmentation maintains the reflector's optical functionality while minimizing dislocation-induced optical loss, thereby improving external quantum 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
This approach effectively reduces dislocations in the reflector, minimizing optical loss and enhancing the external quantum efficiency of the vertical cavity surface emitting laser element.
Implementation Method 1
growing a first semiconductor layer consisting of a group III semiconductor containing aluminum and indium, the growing of the first semiconductor layer consisting of growing a first layer by supplying an aluminum source gas, an indium source gas, and a nitrogen source gas
Data Source
AI summary
A method of manufacturing a vertical cavity surface emitting laser element including a first reflector including a nitride semiconductor multilayer film, the method includes: growing a first semiconductor layer consisting of a group III semiconductor containing aluminum and indium, the growing of the first semiconductor layer consisting of growing a first layer by supplying an aluminum source gas, an indium source gas, and a nitrogen source gas, and growing a second layer by supplying an aluminum source gas, an indium source gas, and a nitrogen source gas so that an indium composition ratio of the second layer is higher than an indium composition ratio of the first layer; and growing a second semiconductor layer consisting of gallium nitride. The growing of the first semiconductor layer and the growing of the second semiconductor are repeated alternately to form the nitride semiconductor multilayer film constituting the first reflector.