GaN Light Emitting Element Mask Layer Substrate Removal
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Solution Overview
Problem
Existing methods for manufacturing surface-emitting laser elements with nitride semiconductors lack a means to suppress variations in the removal amount of the second conductivity type layer, leading to non-uniformity in the resonator length and stability issues in the light emitting element.
Innovation Solution
A method involving the formation of a mask layer for selective growth on the substrate, followed by layering a GaN-based compound semiconductor structure, fixing a light reflecting layer to a support substrate, and removing the substrate while exposing the mask layer or convexity to act as a stopper, thereby controlling the removal process and achieving uniformity in the resonator length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the substrate is removed by CMP method to expose the second conductivity type layer, then the light scattering is suppressed, but the removal amount varies leading to non-uniform resonator length
Solution Approach 1:
A mask layer is formed on the substrate surface before substrate removal. This mask layer serves as a stopper that prevents over-removal and ensures uniform exposure of the second conductivity type layer. The mask layer is formed at a position that will become the future light emission surface, and its thickness is controlled to achieve the desired resonator length uniformity.
Solution Approach 2:
The mask layer acts as an intermediary between the substrate and the second conductivity type layer during the removal process. It controls the removal depth by serving as a physical barrier, ensuring that the substrate is removed uniformly without damaging the underlying layers. The mask layer material is selected to have different etch selectivity compared to the substrate material.
2Reliability
If the resonator length is made uniform by controlling substrate removal, then the light emitting element characteristics are stabilized, but the process complexity increases
Solution Approach 1:
The mask layer is formed in advance before substrate removal, establishing a predetermined stopper position. This preliminary action simplifies the subsequent substrate removal process by providing a clear endpoint indicator, reducing the need for complex real-time monitoring and control systems.
Solution Approach 2:
The mask layer automatically serves as its own thickness reference and stopper indicator. During substrate removal, the mask layer thickness self-regulates the removal depth, eliminating the need for external measurement and control mechanisms. The process is self-limiting, as removal stops when the mask layer is reached.
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 suppresses removal variations and achieves stability in the characteristics of the light emitting element by ensuring uniformity in the resonator length and minimizing light scattering.
Implementation Method 1
forming a mask layer for selective growth formed from a material different from a material that configures a first compound semiconductor layer on a region outside an element forming region
Implementation Method 2
forming a first light reflecting layer formed from a multilayer film and a first electrode on the first surface of the first compound semiconductor layer
Data Source
AI summary
A method of manufacturing a light emitting element includes, sequentially, (a) forming a mask layer for selective growth; (b) forming a layered structure body by layering a first compound semiconductor layer, an active layer, and a second compound semiconductor layer; (c) forming, on the second surface of the second compound semiconductor layer, a second electrode and a second light reflecting layer formed from a multilayer film; (d) fixing the second light reflecting layer to a support substrate; (e) removing the substrate for manufacturing a light emitting element, and exposing the first surface of the first compound semiconductor layer and the mask layer; and (f) forming a first light reflecting layer formed from a multilayer film and a first electrode on the first surface of the first compound semiconductor layer.