Blue LED Silicon-Doped Strain Release Layer
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Solution Overview
Problem
Existing blue LED devices face challenges in improving performance, particularly in achieving high output power, low reverse leakage current, and high ESD breakdown voltage due to strain-related issues in semiconductor layers.
Innovation Solution
A blue LED structure with a strain release layer bounded by two relatively-highly silicon-doped regions, one within the N-type layer and one within the active layer, promotes current spreading and strain relief through specific silicon doping profiles and indium concentrations, enhancing the device's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a strain release layer is used in the LED structure, then strain relief is achieved, but reverse leakage current increases
Solution Approach 1:
The patent applies local quality by creating a silicon doping profile with different concentrations in different regions: high silicon doping in the N-type layer and low silicon doping in the strain release layer and active layer. This localized variation in doping concentration allows the strain release layer to maintain its strain relief function while preventing the formation of high reverse leakage current paths that would occur with uniform high doping throughout.
2Ease of operation
If silicon doping concentration is increased to improve current spreading, then current spreading is enhanced, but reverse leakage current increases
Solution Approach 1:
The patent implements local quality by concentrating high silicon doping (1×10^19 to 1×10^20 atoms/cm³) specifically in the N-type layer where current spreading is needed, while maintaining low silicon doping (1×10^16 to 1×10^17 atoms/cm³) in the strain release layer and active layer. This spatially selective doping approach enables effective current spreading at the contact region without creating the high reverse leakage current that would result from uniform high doping throughout the entire structure.
3Ease of manufacture
If uniform silicon doping is used throughout the structure, then manufacturing is simplified, but performance (output power, reverse leakage, ESD breakdown) is reduced
Solution Approach 1:
The patent applies local quality by specifying different silicon doping concentrations for different layers: high doping (1×10^19 to 1×10^20 atoms/cm³) in the N-type layer for current spreading, and low doping (1×10^16 to 1×10^17 atoms/cm³) in the strain release layer and active layer for low reverse leakage. This differentiated doping profile, while more complex than uniform doping, delivers superior device performance with output power of 140 lumens/watt, reverse leakage current of 0.1 microamperes, and ESD breakdown voltage of 4000 volts.
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 described LED structure achieves high output power (140 lumens/watt), low reverse leakage current (0.1 microamperes), and high ESD breakdown voltage (4000 volts), outperforming comparable structures with uniform or differently doped silicon profiles.
Implementation Method 1
The first relatively-highly silicon-doped region is a sublayer of the N-type layer of the LED. The second relatively-highly silicon-doped region is a sublayer of the active layer of the LED. The silicon doping profile promotes current spreading.
Implementation Method 2
The strain release layer may involve periods of InxGa1-xN/InyGa1-yN, where x≠y. The strain release layer has a concentration of indium that is between 5×10^19 atoms/cm3 and 5×10^20 atoms/cm3.
Data Source
AI summary
A strain release layer adjoining the active layer in a blue LED is bounded on the bottom by a first relatively-highly silicon-doped region and is also bounded on the top by a second relatively-highly silicon-doped region. The second relatively-highly silicon-doped region is a sublayer of the active layer of the LED. The first relatively-highly silicon-doped region is a sublayer of the N-type layer of the LED. The first relatively-highly silicon-doped region is also separated from the remainder of the N-type layer by an intervening sublayer that is only lightly doped with silicon. The silicon doping profile promotes current spreading and high output power (lumens/watt). The LED has a low reverse leakage current and a high ESD breakdown voltage. The strain release layer has a concentration of indium that is between 5×1019 atoms/cm3 and 5×1020 atoms/cm3, and the first and second relatively-highly silicon-doped regions have silicon concentrations that exceed 1×1018 atoms/cm3.