Quantum Well Barrier Band Alignment for Doping Activation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Controlling doping in wide band gap semiconductor materials is difficult due to deep impurity levels and inefficient activation, which limits the conductivity of devices like deep ultraviolet light emitting diodes and transistors.
Innovation Solution
A structure with a quantum well and an adjacent barrier is designed such that 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, facilitating improved conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional doping methods are used in wide band gap semiconductor materials, then the doping process can be performed, but the impurity activation efficiency is low and conductivity is limited
Solution Approach 1:
The patent changes the energy parameter alignment between dopant levels and band edges by adjusting heterostructure composition and band discontinuity to coincide with dopant activation energy, thereby improving impurity activation efficiency from approximately 1% to significantly higher levels
Solution Approach 2:
The patent uses composite heterostructure materials (e.g., AlGaN/GaN) to create specific band discontinuities that align with dopant energy levels, enabling more efficient impurity activation compared to single material systems
2Temperature
If the dopant energy level is deep in the band gap, then the semiconductor material maintains its wide band gap properties, but the activation of impurities becomes inefficient
Solution Approach 1:
The patent changes the effective activation energy parameter by aligning the dopant energy level with the band edge through heterostructure design, allowing deep level dopants to be efficiently activated without reducing the overall band gap of the wide band gap semiconductor material
3Quantity of substance
If polarization doping is used to create hole accumulation layer, then hole sheet density increases, but perpendicular conductance remains extremely small
Solution Approach 1:
The patent changes the energy band alignment parameter by designing target band discontinuity to coincide with dopant activation energy, enabling efficient real space transfer of holes across the barrier and improving perpendicular conductance while maintaining high hole sheet density
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, enhancing the efficiency of hole transfer and improving the conductivity of semiconductor devices, particularly in deep ultraviolet light emitting diodes and transistors.
Implementation Method 1
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... facilitating a real space transfer of holes across the barrier
Implementation Method 2
Polarization doping in GaN-on-AlGaN heterostructures has been shown to lead to the creation of a hole accumulation layer. For example, the polarization charge has been shown to induce a hole sheet density as high as 5×1013 cm−2 at an AlGaN/GaN heterointerface
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).