GaN Optical Device Carbon Doping Stability
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Solution Overview
Problem
III-nitride semiconductor optical devices face challenges with high resistance and complex conduction behaviors due to threading dislocations and the behavior of carbon as a dopant, which complicates crystallographic structures and affects conductivity.
Innovation Solution
A III-nitride semiconductor optical device with a p-type gallium nitride layer doped with carbon and magnesium, where the carbon concentration is between 2×10^16 cm^-3 and 1×10^19 cm^-3, and the angle of the primary surface is between 40 and 140 degrees, stabilizes carbon as a p-type dopant, reducing resistance and maintaining crystal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon is added to GaN film to increase electric resistance, then resistance increases, but conduction behavior becomes complicated and crystal quality deteriorates
Solution Approach 1:
The patent changes the doping parameter from conventional Mg-only doping to dual doping with Mg and C, where C concentration is controlled within 1×10^18 to 1×10^19 atoms/cm³. This parameter change stabilizes the p-type conduction behavior and prevents the complicated conduction phenomena observed in conventional high-resistance GaN films.
Solution Approach 2:
The patent creates a composite doped structure by combining Mg and C dopants in the GaN film. This composite doping approach produces a synergistic effect where C atoms fill interstitial sites and passivate defects, while Mg provides holes, resulting in stable p-type conduction with high resistance without the complicated conduction behaviors seen in single-dopant systems.
2Reliability
If Mg doping is increased to achieve desired hole concentration, then hole concentration increases, but crystal quality deteriorates
Solution Approach 1:
The patent introduces C atoms as an intermediary substance that mediates between Mg dopants and the GaN crystal lattice. The C atoms fill interstitial sites and passivate defects, allowing Mg to provide holes effectively without degrading crystal quality. This intermediary action enables achieving desired hole concentration while maintaining high crystal quality.
Solution Approach 2:
The patent changes the doping strategy from high Mg concentration to a combination of Mg and C doping with optimized concentrations. By controlling C concentration within 1×10^18 to 1×10^19 atoms/cm³, the system achieves the desired hole concentration with reduced Mg content, thereby preventing crystal quality deterioration.
3Ease of manufacture
If heterojunctions are included in GaN growth on Si substrate, then growth is enabled, but threading dislocations increase and conduction becomes complicated
Solution Approach 1:
The patent converts the harmful effect of threading dislocations into a beneficial outcome by using C doping. The C atoms fill interstitial sites and passivate defects, including threading dislocations, transforming the high-dislocation-density situation into an advantage where the GaN film achieves stable p-type conduction and high resistance despite the heterojunction structure.
Solution Approach 2:
The patent changes the electrical and structural parameters of the GaN film by introducing C doping. This parameter change compensates for the negative effects of threading dislocations introduced by heteroepitaxial growth on Si substrates, achieving stable p-type conduction with hole concentration of 1×10^18 to 1×10^19 atoms/cm³ and resistance of 10^-3 to 10^-2 ohm·cm.
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 solution reduces resistance and improves crystal quality by stabilizing carbon as a p-type dopant, allowing for efficient hole concentration and electrical conductivity while minimizing the impact on n-type conductivity and emission characteristics.
Implementation Method 1
the p-type gallium nitride based semiconductor layer contains carbon as a p-type dopant
Implementation Method 2
carbon can be stably utilized as a p-type dopant in the GaN-based semiconductors
Implementation Method 3
Sample (A) exhibited p-type conduction and Sample (B) n-type conduction
Data Source
AI summary
A III-nitride semiconductor optical device has a support base comprised of a III-nitride semiconductor, an n-type gallium nitride based semiconductor layer, a p-type gallium nitride based semiconductor layer, and an active layer. The support base has a primary surface at an angle with respect to a reference plane perpendicular to a reference axis extending in a c-axis direction of the III-nitride semiconductor. The n-type gallium nitride based semiconductor layer is provided over the primary surface of the support base. The p-type gallium nitride based semiconductor layer is doped with magnesium and is provided over the primary surface of the support base. The active layer is provided between the n-type gallium nitride based semiconductor layer and the p-type gallium nitride based semiconductor layer over the primary surface of the support base. The angle is in the range of not less than 40° and not more than 140°. The primary surface demonstrates either one of semipolar nature and nonpolar nature. The p-type gallium nitride based semiconductor layer contains carbon as a p-type dopant. A carbon concentration of the p-type gallium nitride based semiconductor layer is not less than 2×1016 cm−3, and the carbon concentration of the p-type gallium nitride based semiconductor layer is not more than 1×1019 cm−3.