Oxygen-Doped Silver Mirror for Low Contact Resistance in LED Chips
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Solution Overview
Problem
Optoelectronic semiconductor chips, such as light emitting diodes, face challenges in achieving low contact resistance and maintaining high reflectivity for efficient radiation emission, particularly in the blue spectral range, due to the use of materials like platinum or nickel which reduce reflectivity despite lowering contact resistance.
Innovation Solution
Incorporating a silver mirror with a controlled amount of oxygen, typically between 10^-5 and 10% by weight, to reduce contact resistance without significantly affecting reflectivity, and using a silver mirror composed of silver and oxygen with minimal impurities to enhance energy-efficient radiation emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If materials like platinum or nickel are used to reduce contact resistance, then contact resistance decreases, but reflectivity decreases
Solution Approach 1:
The patent changes the chemical composition parameter of the silver mirror by introducing oxygen at controlled concentrations (10^-5 to 10% by weight). This parameter change allows the silver mirror to simultaneously achieve low contact resistance with the semiconductor layer and maintain high reflectivity for blue light, resolving the contradiction between electrical contact quality and optical performance
Solution Approach 2:
The patent creates a composite material system where oxygen is incorporated into the silver mirror structure. This composite silver-oxygen material exhibits both low contact resistance properties and high reflectivity properties, combining the beneficial characteristics that were previously mutually exclusive when using pure metals like platinum or nickel
2Use of energy by moving object
If a silver mirror is used to maintain high reflectivity, then reflectivity increases, but contact resistance increases
Solution Approach 1:
By adjusting the oxygen concentration parameter in the silver mirror to specific ranges (particularly 10^-4 to 10^-2% by weight), the patent optimizes both electrical and optical properties. This parameter optimization allows pure silver to maintain its high reflectivity while the introduced oxygen reduces contact resistance, reversing the traditional trade-off
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
The silver mirror with oxygen content achieves low contact resistance and maintains high reflectivity, leading to efficient radiation emission, particularly in the blue spectral range, thereby improving the energy efficiency of the semiconductor chip.
Implementation Method 1
The silver mirror is arranged at the semiconductor layer sequence and designed to reflect the radiation generated in the active layer, in particular in a direction toward a radiation exit area of the semiconductor chip
Implementation Method 2
In order to reduce the contact resistance it is possible to fit an intermediate layer between a mirror and the semiconductor layer sequence... a comparatively small amount of oxygen in the silver mirror
Data Source
AI summary
In at least one embodiment, the optoelectronic semiconductor chip comprises a semiconductor layer sequence for generating an electromagnetic radiation, and also a silver mirror. The silver mirror is arranged at the semiconductor layer sequence. Oxygen is admixed with the silver of the silver mirror. A proportion by weight of the oxygen in the silver mirror is preferably at least 10−5 and furthermore preferably at most 10%.