Semi-Polar GaN Laser Pad Electrode Design for COD Prevention
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Solution Overview
Problem
Group III nitride semiconductor laser devices face issues with abnormal growth of dielectric material at the pad electrode, leading to catastrophic optical damage (COD) and reduced heat dissipation, particularly due to the end faces not being formed by cleaving.
Innovation Solution
A group III nitride semiconductor laser device structure is designed with a semi-polar primary surface, inclined c-axis, and a pad electrode configuration where the third electrode portion is positioned away from the edge of the end face, facilitating heat dissipation and preventing abnormal growth of dielectric material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the pad electrode extends to the edge of the end face, then heat dissipation capability is improved, but abnormal growth of dielectric material occurs leading to COD
Solution Approach 1:
The pad electrode is designed with different regions having different functions: the first electrode portion extends to the edge for heat dissipation, while the third electrode portion is positioned away from the edge to prevent dielectric material abnormal growth. This local differentiation resolves the contradiction between heat dissipation and COD prevention.
2Ease of manufacture
If the end faces are not formed by cleaving, then manufacturing flexibility is improved, but abnormal growth of dielectric material is triggered
Solution Approach 1:
The third electrode portion is positioned away from the edge of the end face in advance to prevent the triggering of abnormal dielectric material growth. This preliminary structural arrangement counteracts the harmful effect before it occurs during dielectric multilayer formation.
3Reliability
If the pad electrode is positioned away from the edge, then abnormal growth is prevented, but heat dissipation capability is reduced
Solution Approach 1:
The pad electrode is segmented into multiple portions: the first electrode portion extends to the edge to maintain heat dissipation capability, while the third electrode portion is positioned away from the edge to prevent abnormal growth. This segmentation allows both contradictory requirements to be satisfied simultaneously in different regions.
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 configuration reduces the occurrence of malfunctions due to COD and enhances heat dissipation, thereby extending the life of the laser device and maintaining the quality of the dielectric multilayer.
Implementation Method 1
a laser structure including a support base and a semiconductor region, the support base having a semi-polar primary surface and comprising a hexagonal group III nitride semiconductor
Implementation Method 2
the heat generated near a light-emitting face is dissipated through the pad electrode during laser operation
Data Source
AI summary
A group III nitride semiconductor laser device includes a laser structure, an insulating layer, an electrode and dielectric multilayers. The laser structure includes a semiconductor region on a semi-polar primary surface of a hexagonal group III nitride semiconductor support base. The dielectric multilayers are on first and second end-faces for the laser cavity. The c-axis of the group III nitride tilts by an angle ALPHA from the normal axis of the primary surface in the waveguide axis direction from the first end-face to the second end-faces. A pad electrode has first to third portions provided on the first to third regions of the semiconductor regions, respectively. An ohmic electrode is in contact with the third region through an opening of the insulating layer. The first portion has a first arm, which extends to the first end-face edge. The third portion is away from the first end-face edge.