Light-Emitting Epitaxial Structure for Dopant Diffusion Control
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Solution Overview
Problem
Light-emitting devices face challenges in maintaining high luminous intensity and efficiency due to diffusion of n-type and p-type dopants into the active layer, which affects lattice quality and performance.
Innovation Solution
A semiconductor epitaxial structure is designed with specific doping concentrations and distances between semiconductor layers and the active layer to control dopant diffusion, incorporating well and barrier layers in the active layer and spacing layers to prevent dopant diffusion, thereby improving lattice quality and photoelectric performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If higher doping concentration is used in semiconductor layers to increase electrons and holes, then carrier concentration is improved, but dopant diffusion into active layer increases affecting lattice quality
Solution Approach 1:
The patent introduces an undoped or low-doped GaN layer as an intermediary barrier between the high-doping-concentration semiconductor layers and the active layer. This intermediate layer prevents direct diffusion of dopants into the active layer while still allowing sufficient carrier supply to the active region, thus resolving the contradiction between maintaining high carrier concentration and preserving lattice quality.
Solution Approach 2:
The patent segments the semiconductor layer into multiple sub-layers with different doping concentrations: a first semiconductor layer with high doping concentration for carrier supply, an undoped or low-doped GaN intermediate layer for diffusion prevention, and a second semiconductor layer with high doping concentration. This segmentation allows each layer to perform its specific function optimally.
2Use of energy by moving object
If higher doping concentration is used to improve luminous efficiency, then light emission efficiency is improved, but dopant diffusion affects active layer performance
Solution Approach 1:
The undoped or low-doped GaN intermediate layer acts as a protective intermediary that blocks dopant diffusion into the active layer, thereby protecting active layer performance and reliability while allowing the adjacent high-doping semiconductor layers to maintain high luminous efficiency through sufficient carrier supply.
Solution Approach 2:
The patent applies different doping concentrations to different regions: high doping concentration in the semiconductor layers for efficient carrier generation and low or zero doping concentration in the intermediate layer for diffusion blocking. This local quality differentiation allows simultaneous optimization of luminous efficiency and active layer reliability.
3Productivity
If distance between semiconductor layer and active layer is reduced to improve carrier injection, then injection efficiency is improved, but dopant diffusion into active layer increases
Solution Approach 1:
The patent inserts an undoped or low-doped GaN intermediate layer between the semiconductor layer and the active layer. This intermediate layer serves as a diffusion barrier that prevents dopant migration even when the physical distance between the high-doping semiconductor layer and active layer is small, thus maintaining both high carrier injection efficiency and preventing harmful dopant diffusion.
Solution Approach 2:
The patent extracts the dopant-containing regions from direct contact with the active layer by removing dopants from the intermediate GaN layer. This extraction of the harmful dopant element from the critical interface region allows close proximity for efficient carrier injection without the risk of dopant diffusion.
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 controlled dopant diffusion enhances the luminous intensity and efficiency of the light-emitting device by maintaining better lattice quality and uniform current spreading, leading to improved optoelectronic performance.
Implementation Method 1
Due to diffusion and memory effect of the n-type dopant and the p-type dopant, the n-type dopant and the p-type dopant are more likely to diffuse into the active layer
Data Source
AI summary
A light-emitting device includes a semiconductor epitaxial structure that has a first surface and a second surface opposite to the first surface, and that includes a first semiconductor layer, an active layer, and a second semiconductor layer sequentially disposed in such order in a direction from the first surface to the second surface. The active layer includes well layers and barrier layers that are alternately stacked. The active layer has an upper surface that is adjacent to the second semiconductor layer, and a lower surface that is opposite to the upper surface. The first semiconductor layer is doped with an n-type dopant, which has a first concentration of 5E17/cm3 at a first point in the first semiconductor layer. The first point of the first semiconductor layer and the lower surface of the active layer have a first distance therebetween. The first distance ranges from 150 nm to 500 nm.