Quantum Well Band Alignment for Dopant Activation
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Solution Overview
Problem
Controlling doping in wide band gap semiconductor materials, particularly in AlGaN, is challenging due to deep impurity levels and inefficient activation, which limits the conductivity of p-type devices such as deep ultraviolet light emitting diodes (LEDs).
Innovation Solution
A method of designing and fabricating a structure with a quantum well and an adjacent barrier, where the target band discontinuity coincides with the dopant's activation energy, allowing for efficient real space transfer of holes by aligning the dopant energy level with the valence energy band edge or ground state energy of the quantum well, and selecting appropriate doping levels to facilitate this transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional doping methods are used in wide band gap semiconductor materials, then the doping process is simple, but the impurity activation is inefficient and conductivity is limited
Solution Approach 1:
The patent introduces an intermediate layer with specific band structure between the contact and the wide band gap semiconductor layer. This intermediate layer acts as a mediator that facilitates carrier transport and improves impurity activation efficiency by providing energy level alignment that enables more effective doping, thereby resolving the contradiction between activation efficiency and manufacturing simplicity.
Solution Approach 2:
The patent changes the band structure parameters of the semiconductor layers by selecting specific materials with appropriate band gaps and energy levels. By adjusting the band alignment parameters through material selection and layer design, the patent achieves efficient impurity activation and enhanced conductivity while maintaining controllable doping processes.
2Reliability
If the dopant energy level is deep in the band gap, then the material maintains its wide band gap properties, but the activation energy is high and conductivity is reduced
Solution Approach 1:
The intermediate layer serves as an energy mediator that provides a stepped energy pathway for carrier activation. By introducing this intermediate structure with optimized energy levels, the patent reduces the effective activation energy required for dopant ionization while preserving the wide band gap characteristics of the main semiconductor layer, thus improving conductivity without increasing energy consumption.
Solution Approach 2:
The patent segments the energy band structure into multiple levels through the intermediate layer, creating a stepped energy profile. This segmentation divides the large energy gap into smaller steps, making it easier for carriers to overcome the activation barrier through multiple lower-energy transitions rather than a single high-energy jump, thereby reducing effective activation energy while maintaining overall band gap properties.
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 approach reduces the activation energy for dopants in the barrier, enabling more efficient real space transfer of holes, thereby enhancing the conductivity of semiconductor devices like deep ultraviolet LEDs.
Implementation Method 1
enabling more efficient real space transfer of holes
Implementation Method 2
the target band discontinuity coincides with an activation energy of a dopant
Data Source
AI summary
A solution for designing and/or fabricating a structure including a quantum well and an adjacent barrier is provided. A target band discontinuity between the quantum well and the adjacent barrier is selected to coincide with an activation energy of a dopant for the quantum well and/or barrier. For example, a target valence band discontinuity can be selected such that a dopant energy level of a dopant in the adjacent barrier coincides with a valence energy band edge for the quantum well and/or a ground state energy for free carriers in a valence energy band for the quantum well. Additionally, a target doping level for the quantum well and/or adjacent barrier can be selected to facilitate a real space transfer of holes across the barrier. The quantum well and the adjacent barrier can be formed such that the actual band discontinuity and/or actual doping level(s) correspond to the relevant target(s).