Nitride Semiconductor Ridge Electrode Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor devices using nitride semiconductors face issues with increased contact resistance and light absorption by electrodes, leading to reduced slope efficiency and operating voltage challenges.
Innovation Solution
A semiconductor device with a stripe-shaped ridge and an electrode having a flat portion and sloped portions on both sides, where a protective film covers the sides of the ridge and sloped electrode portions, preventing light absorption and improving contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the width of the ridge is increased to prevent increase in contact resistance, then contact resistance decreases, but the laser beam becomes multimode and electrode area increases causing light absorption and reduced slope efficiency
Solution Approach 1:
The electrode is divided into multiple segments along the ridge width direction, with insulating films placed between segments. This segmentation allows the electrode to cover a wider ridge area for lower contact resistance while preventing continuous light absorption across the entire electrode width, as the insulating films create optical isolation between electrode segments.
Solution Approach 2:
Insulating films are introduced as intermediary elements between adjacent electrode regions. These insulating films serve dual functions: electrically isolating adjacent electrode segments to prevent short circuits, and optically isolating them to prevent light absorption by the electrode while maintaining electrical connectivity where needed.
2Reliability
If the contact area between electrode and ridge is increased to reduce contact resistance, then contact resistance decreases, but laser operating voltage increases due to light absorption
Solution Approach 1:
The electrode is segmented into multiple independent contact regions along the ridge, allowing each segment to provide electrical contact while the insulating films between segments prevent cumulative light absorption that would increase operating voltage. This enables wide ridge coverage for low contact resistance without the penalty of continuous light absorption.
Solution Approach 2:
Insulating films act as intermediary elements that electrically isolate adjacent electrode segments while allowing optical isolation. This prevents the electrode from absorbing laser light across its entire width, thereby reducing the increase in laser operating voltage that would otherwise occur with larger electrode areas.
3Ease of manufacture
If insulating film is not formed on the upper surface of the ridge, then manufacturing is simpler, but light absorption by the electrode occurs reducing slope efficiency
Solution Approach 1:
The insulating film is applied selectively only to specific regions where light absorption would be problematic, rather than covering the entire ridge surface. This local application prevents light absorption by the electrode in critical areas while maintaining manufacturing simplicity by avoiding complete ridge coverage.
Solution Approach 2:
Insulating films are strategically placed as intermediary elements between the ridge surface and electrode in regions where light absorption would occur. This targeted approach prevents light absorption without requiring comprehensive insulating coverage, balancing manufacturing simplicity with optical performance.
Data Source
Figure 1
Figure 2a~2b
Figure 2c~2d
AI summary
A semiconductor device includes a semiconductor layer stacked on a substrate, a stripe-shaped ridge formed on a surface of the semiconductor layer, and electrode formed on an upper surface of the ridge and a protective film disposed on each side of the ridge. The electrode includes a flat portion having a flat surface substantially parallel to the upper surface of the ridge and sloped portions on both sides of the flat portion with each of the sloped portions having a sloped surface that is sloped with respect to the upper surface of the ridge. The protective film covers a region from a side surface of the ridge to the sloped surface of the sloped portion of the electrode.