GaN Light-Emitting Element Impurity Diffusion Barrier
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Solution Overview
Problem
GaN-based semiconductor light-emitting elements with superlattice structures do not achieve sufficient hole concentration, leading to inadequate light emission efficiency.
Innovation Solution
Incorporating an impurity diffusion-preventing layer of undoped GaN-based compound semiconductor between the active layer and the second GaN-based compound semiconductor layer, and a laminated structure or a third GaN-based compound semiconductor layer, to enhance hole concentration and light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a superlattice structure is used in the second GaN-based compound semiconductor layer, then hole concentration is increased, but light emission efficiency remains insufficient
Solution Approach 1:
The second GaN-based compound semiconductor layer is divided into multiple sub-layers with different doping concentrations (first sub-layer with higher doping concentration adjacent to active layer, second sub-layer with lower doping concentration). This segmentation allows optimized hole supply to the active layer while maintaining overall layer functionality, resolving the contradiction between achieving sufficient hole concentration and improving light emission efficiency.
2Reliability
If doping concentration is increased to improve hole concentration, then light emission efficiency improves, but impurity diffusion into the active layer occurs
Solution Approach 1:
Different regions of the second GaN-based compound semiconductor layer are assigned different doping concentrations locally. The first sub-layer adjacent to the active layer has a higher doping concentration to supply holes, while the second sub-layer has a lower doping concentration to prevent impurity diffusion. This local quality differentiation resolves the contradiction between improving light emission efficiency and maintaining active layer purity.
Solution Approach 2:
The second GaN-based compound semiconductor layer acts as an intermediary between the active layer and the contact layer, with its graded doping structure mediating the balance between hole supply and impurity diffusion prevention. The layer transitions from higher doping near the active layer to lower doping further away, optimizing both hole concentration and impurity barrier functions.
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 proposed structure significantly increases light emission efficiency across a wide range of operating current densities, improving the performance of GaN-based semiconductor light-emitting elements.
Implementation Method 1
an impurity diffusion-preventing layer composed of an undoped GaN-based compound semiconductor, the impurity diffusion-preventing layer preventing a p-type impurity from diffusing into the active layer
Implementation Method 2
high hole concentrations are obtained two-dimensionally by the piezoelectric effect due to strain
Data Source
AI summary
A GaN-based semiconductor light-emitting element includes a first GaN-based compound semiconductor layer of n-conductivity type, an active layer, a second GaN-based compound semiconductor layer of p-conductivity type, a first electrode electrically connected to the first GaN-based compound semiconductor layer, a second electrode electrically connected to the second GaN-based compound semiconductor layer, an impurity diffusion-preventing layer composed of an undoped GaN-based compound semiconductor, the impurity diffusion-preventing layer preventing a p-type impurity from diffusing into the active layer, and a laminated structure or a third GaN-based compound semiconductor layer of p-conductivity type. The impurity diffusion-preventing layer and the laminated structure or the third GaN-based compound semiconductor layer of p-conductivity type are disposed, between the active layer and the second GaN-based compound semiconductor layer, in that order from the active layer side.