P-type AlGaN Semiconductor Hole Concentration via Mg Doping
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Solution Overview
Problem
Achieving high hole concentration and efficient p-type conductivity in group III nitride semiconductors with high Al content, such as AlXGaYInZN, is challenging due to increased activation energy and carrier compensation, making it difficult to produce effective ultraviolet light emitting diodes and laser diodes.
Innovation Solution
Doping acceptor impurity atoms at specific concentrations (5×10^18 to 1×10^20 cm^-3) in AlXGaYInZN semiconductors using the metal organic chemical vapor deposition method, which enhances hole formation efficiency and results in good p-type properties, despite defying conventional understanding of resistivity and hole concentration relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If acceptor impurity atom is doped in high concentration (10^21 cm^-3 or more) to achieve high hole concentration in AlXGaYInZN with Al composition of 70%, then hole concentration increases, but many crystal defects are introduced and donor-type compensation center is formed, making it difficult to attain high hole concentration
Solution Approach 1:
The patent changes the concentration parameter of acceptor impurity atoms from conventional high concentration (10^21 cm^-3 or more) to a specific range (5×10^18 to 1×10^20 cm^-3). This parameter change resolves the contradiction by achieving sufficient hole concentration (10^16 cm^-3 or more) without introducing excessive crystal defects and donor-type compensation centers that occur at higher doping concentrations.
2Use of energy by moving object
If Al content is increased to achieve deep ultraviolet emission (300 nm or less), then emission wavelength decreases, but activation energy of acceptor impurity atom increases and carrier compensation occurs, making p-type conduction difficult
Solution Approach 1:
The patent changes the acceptor impurity atom concentration parameter to a specific range (5×10^18 to 1×10^20 cm^-3) that is optimized for high Al content materials (X≧0.5). This resolves the contradiction by achieving sufficient hole concentration despite the increased activation energy and carrier compensation that occur at high Al content, enabling p-type conduction in deep ultraviolet emitting materials.
3Quantity of substance
If acceptor impurity atom concentration is increased to achieve high hole concentration, then hole concentration increases, but resistivity exponentially increases at room temperature according to conventional understanding
Solution Approach 1:
The patent changes the acceptor impurity atom concentration to a specific range (5×10^18 to 1×10^20 cm^-3) that optimizes both hole concentration and resistivity. This resolves the contradiction by achieving high hole concentration (10^16 cm^-3 or more) while maintaining acceptable resistivity levels, defying the conventional understanding that higher doping always leads to exponentially increased resistivity at room temperature.
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 allows for the production of p-type group III nitride semiconductors with low resistivity and high hole concentration, improving the efficiency of semiconductor devices like light emitting diodes and laser diodes operating in the deep ultraviolet region.
Implementation Method 1
Doping acceptor impurity atoms at specific concentrations (5×10^18 to 1×10^20 cm^-3) in AlXGaYInZN semiconductors using the metal organic chemical vapor deposition method
Data Source
AI summary
This invention provides a p-type group III nitride semiconductor, with good p-type properties, having a composition expressed by AlXGaYInZN in which each of X, Y and Z indicates a rational number satisfying a relationship of X+Y+Z=1.0, even if Al content is as high as 1.0>X≧0.5. It is achieved that a proportion of a hole concentration at 30° C. to an acceptor impurity atom concentration is 0.001 or more in the p-type group III nitride semiconductor of the invention, by doping acceptor impurity atoms such as Mg in concentration of 5×1018 to 1×1020 cm−3 using the method, for example, MOCVD with attention not to incorporate an impurity atom other than the acceptor impurity atom or not to form dislocation in the crystal when producing the group III nitride semiconductor expressed by the above composition.