Method of manufacturing surface-emitting laser element
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in manufacturing photonic-crystal surface-emitting lasers lies in controlling the oscillation wavelength and emission light characteristics with high accuracy, particularly due to the difficulty in accurately controlling the optical path length of semiconductor layers, which affects the interference between direct and reflected diffracted light, leading to inconsistent slope efficiency.
Innovation Solution
A method involving the formation of a photonic crystal layer on a translucent substrate, followed by crystal growth of active and conductivity-type semiconductor layers, with spectrometry to measure the layer thickness and form a translucent electrode and light reflection layer, ensuring the interference light intensity of direct and reflected diffracted light is greater than the direct diffracted light intensity, thereby optimizing emission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the optical path length of the semiconductor layer is controlled by adjusting layer thickness during crystal growth, then the oscillation wavelength and emission characteristics can be controlled, but it is very difficult to achieve high accuracy in layer thickness control
Solution Approach 1:
The patent applies preliminary action by measuring the optical path length of the semiconductor layer before forming the reflective electrode. Spectrometry is performed on the semiconductor layer to obtain the optical path length, which is then used to calculate the appropriate thickness for the translucent electrode. This preliminary measurement approach allows for accurate determination of the optical path length without requiring extremely precise control of the semiconductor layer thickness during crystal growth, thereby resolving the contradiction between manufacturing precision and measurement precision.
2Ease of manufacture
If the semiconductor layer thickness is not precisely controlled, then manufacturing is easier, but the interference between direct diffracted light and reflected diffracted light cannot be accurately controlled, leading to inconsistent slope efficiency
Solution Approach 1:
The patent implements feedback by using spectrometry to measure the optical path length of the semiconductor layer after crystal growth. The measured optical path length is then fed back into the design process to determine the appropriate thickness of the translucent electrode and the configuration of the reflective electrode. This feedback mechanism ensures that the interference between direct diffracted light and reflected diffracted light is accurately controlled, achieving consistent slope efficiency without requiring extremely precise initial control of the semiconductor layer thickness.
3Manufacturing precision
If the layer thickness is controlled with high accuracy to determine optical path length, then emission characteristics can be precisely controlled, but manufacturing complexity and difficulty increase significantly
Solution Approach 1:
The patent replaces the mechanical approach of precisely controlling layer thickness during crystal growth with an optical measurement approach. Instead of relying on precise mechanical control of the semiconductor layer thickness, the invention uses spectrometry to measure the optical path length optically. This substitution simplifies the manufacturing process by eliminating the need for extremely precise mechanical thickness control while still achieving accurate determination of the optical path length for subsequent electrode design.
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 enables precise control over the oscillation wavelength and emission light characteristics, achieving high slope efficiency and improved yield in photonic-crystal surface-emitting lasers by accurately determining the layer thickness through spectral reflection measurement.
Implementation Method 1
light oscillated due to two-dimensional in-plane resonance in a photonic crystal layer is diffracted in a direction perpendicular to the plane
Implementation Method 2
light diffracted in an opposite direction and reflected by a reflection surface
Implementation Method 3
light diffracted from the photonic crystal layer toward the substrate side (direct diffracted light) and light diffracted in an opposite direction and reflected by a reflection surface (reflected diffracted light) interfere with each other
Implementation Method 4
emitted light is extracted from a substrate side
Data Source
AI summary
A method of manufacturing a surface-emitting laser, includes (a) forming a first semiconductor layer including a photonic-crystal (PC) layer, (b) growing, on the first semiconductor layer, an active layer and a second semiconductor layer, (c) performing spectrometry in which a thickness from a surface of the second semiconductor layer to a position where the spectrometry light is reflected by the PC layer is measured, (d) forming a translucent electrode having a thickness calculated based on an optical path length corresponding to the thickness obtained by the spectrometry on the second semiconductor layer, and (e) forming a reflection layer on the translucent electrode, in which the layer thickness of the translucent electrode is determined such that a light intensity of interference light of (i) direct diffracted light radiated from the PC layer and (ii) reflected diffracted light radiated from the PC layer and reflected by the reflection layer is larger than a light intensity of the direct diffracted light.