Optoelectronic Semiconductor Chip Inversion for Piezoelectric Field Control
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Solution Overview
Problem
Optoelectronic semiconductor chips with hexagonal compound semiconductor active regions face challenges in internal quantum efficiency due to unfavorable piezoelectric field barriers, which hinder charge carrier injection and lead to efficiency drops with increasing current density.
Innovation Solution
The chip design features a sequence of p-doped barrier layer, active region based on III-V semiconductor material, and n-doped barrier layer, where the p-doped barrier layer is positioned closer to the growth substrate, followed by the active region, and then the n-doped barrier layer, aligning with the crystallographic c-axis, to utilize piezoelectric fields for enhanced charge carrier capture, along with a diffusion barrier to prevent dopant contamination and a tunnel contact for efficient current transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional layer sequence (n-doped barrier layer, active region, p-doped barrier layer) is used, then the structure is simple to manufacture, but the piezoelectric fields create barriers that reduce charge carrier injection efficiency and cause internal quantum efficiency to drop with increasing current density
Solution Approach 1:
The patent inverts the conventional layer sequence by placing the p-doped barrier layer closer to the growth substrate and the n-doped barrier layer farther away. This inversion changes the interaction between piezoelectric fields and charge carriers, transforming the fields from barriers into beneficial forces that enhance charge carrier capture in the active region, thereby improving internal quantum efficiency without significantly increasing manufacturing complexity
Solution Approach 2:
The patent changes the spatial arrangement parameter of the barrier layers relative to the growth substrate. By switching the positions of p-doped and n-doped barrier layers, the patent modifies the electric field distribution and piezoelectric field interactions, enabling efficient charge carrier injection and maintaining high internal quantum efficiency across varying current densities
2Reliability
If the p-doped barrier layer is positioned closer to the active region, then charge carrier injection is improved, but dopant diffusion into the active region increases causing contamination
Solution Approach 1:
The patent introduces an undoped barrier layer as an intermediary between the p-doped barrier layer and the active region. This intermediate layer acts as a diffusion barrier that prevents p-type dopants from migrating into the active region, while still allowing the beneficial electric field effects to enhance charge carrier injection efficiency
Solution Approach 2:
The patent segments the barrier structure into multiple functional layers: a p-doped barrier layer for electric field control, an undoped barrier layer for dopant diffusion prevention, and an n-doped barrier layer for additional field control. This segmentation allows each layer to perform its specific function without interfering with the others, resolving the contradiction between injection efficiency and contamination prevention
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
This configuration improves charge carrier capture, making internal quantum efficiency nearly independent of current density, resulting in improved light output and reduced operating voltage, while maintaining efficiency across varying current intensities.
Implementation Method 1
unfavorable piezoelectric field barriers, which hinder charge carrier injection
Implementation Method 2
electromagnetic radiation is generated in the active region by recombination of charge carriers
Implementation Method 3
a diffusion barrier to prevent dopant contamination
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3~4
AI summary
The application relates to an optoelectronic semiconductor chip (20) comprising the following sequence of regions in a growth direction (s) of the semiconductor chip (20): - a p-doped barrier layer (1), for an active region (2), - the active region (2), which is suitable for generating electromagnetic radiation, the active region being based on a hexagonal compound semiconductor, and - an n-doped barrier layer (3) for the active region (2). The application furthermore relates to a component comprising such a semiconductor chip (20) and to a method for producing such a semiconductor chip (20).