Laser Diode Bar Selective Emitter Connection
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Solution Overview
Problem
The production of efficient laser diode bars based on nitride compound semiconductors is challenging due to high defect densities, leading to some emitters not contributing to radiation emission while consuming power and contributing to heating, thus reducing efficiency.
Innovation Solution
A method where emitters are tested for optical and electrical properties, and only those within a specified range are electrically connected, while defective emitters are isolated with an electrically insulating layer to prevent current flow, thereby reducing power consumption and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all emitters in a laser diode bar are electrically connected, then the device complexity is reduced and manufacturing is simplified, but defective emitters consume power and generate heat without contributing to radiation emission, reducing overall efficiency
Solution Approach 1:
The patent applies preliminary action by testing the optical and electrical properties of each emitter before final electrical connection. Emitters are evaluated during or after growth, and only those meeting specified criteria are electrically connected. This prevents defective emitters from being connected in the first place, eliminating energy waste before operation begins.
Solution Approach 2:
The patent implements local quality by differentiating the electrical connection status of individual emitters based on their specific performance characteristics. Instead of uniform connection, each emitter is assessed and connected selectively - functional emitters receive electrical connections while defective ones do not, creating local variations in connectivity matched to local emitter quality.
2Loss of energy
If defective emitters are tested and isolated, then energy efficiency is improved by preventing current flow to non-functional emitters, but the manufacturing process complexity increases due to additional testing and selective connection steps
Solution Approach 1:
Testing for optical and electrical properties is performed preliminarily, either during the semiconductor layer growth process or immediately afterward before final electrical connection. This timing allows defect identification early in manufacturing, enabling selective connection decisions without adding significant process complexity to the overall production flow.
Solution Approach 2:
The growth process itself provides information about emitter quality through in-situ monitoring of optical and electrical properties. The system uses self-generated data from the growth process to identify functional emitters, reducing the need for separate complex testing equipment and procedures outside the growth chamber.
3Reliability
If emitters are tested for optical and electrical properties, then the reliability of radiation emission is improved, but the production time increases due to additional testing steps
Solution Approach 1:
Property testing is conducted preliminarily during or immediately after the growth process, before the semiconductor layers are fully removed from the substrate. This timing allows testing to be integrated into the existing manufacturing sequence without adding significant post-processing time, as emitters are evaluated while still in place on the growth substrate.
Solution Approach 2:
The testing process maintains continuity by evaluating emitter properties without interrupting the overall manufacturing flow. Testing occurs as part of the growth process or immediately upon completion, allowing seamless transition from growth to selection to final connection, minimizing idle time between manufacturing stages.
Data Source
AI summary
A diode bar and a method for producing a laser diode bar are disclosed. In an embodiment a laser diode bar includes a plurality of emitters arranged side by side, the each emitter having a semiconductor layer sequence with an active layer suitable for generating laser radiation, a p-contact and an n-contact, wherein the emitters comprise a group of electrically contacted first emitters and a group of non-electrically contacted second emitters, wherein the p-contacts of the first emitters are electrically contacted by a p-connecting layer, and wherein the p-contacts of the second emitters are separated from the p-connecting layer by an electrically insulating layer and are not electrically contacted.