Co-doped SiC Semiconductor Region for Resistance Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in manufacturing semiconductor devices using silicon carbide (SiC) is the difficulty in lowering resistance in p-type and n-type impurity regions due to low solid solubility limits and deep impurity levels in the band gap, which hinders the development of efficient power semiconductor devices.
Innovation Solution
The implementation of co-doping techniques involving specific combinations of p-type and n-type impurities such as aluminum (Al), gallium (Ga), indium (In), nitrogen (N), boron (B), and phosphorus (P) in SiC, where the concentration ratio of these impurities is optimized between 0.40 and 0.95, forming stable pair or trimer structures that reduce strain and enhance impurity solubility, thereby lowering resistance and improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional single-type doping is used in SiC, then the doping process is simple, but the resistance in impurity regions cannot be lowered sufficiently due to low solid solubility limits
Solution Approach 1:
The patent combines p-type and n-type impurities into a co-doping process, where multiple impurity types are introduced simultaneously or sequentially into the SiC crystal structure. This merging of doping types enables the formation of pair or trimer structures that increase overall impurity solubility and reduce resistance more effectively than single-type doping alone.
Solution Approach 2:
The patent changes the doping parameters by optimizing the concentration ratio of p-type to n-type impurities within a specific range (0.40 to 0.95). This parameter optimization ensures that the co-doped regions achieve maximum resistance reduction while maintaining crystal structure stability and avoiding excessive complexity in the doping process.
2Reliability
If higher impurity concentration is introduced to lower resistance, then resistance decreases, but crystal defects increase due to exceeding solid solubility limits
Solution Approach 1:
The patent creates a composite impurity structure within the SiC crystal by combining p-type and n-type impurities in specific ratios. This composite doping approach forms stable pair or trimer structures that allow higher total impurity concentrations to be incorporated into the crystal lattice without causing excessive defects, thereby reducing resistivity while maintaining crystal stability.
Solution Approach 2:
The patent optimizes the concentration ratio parameter of p-type to n-type impurities (0.40 to 0.95) to achieve the最佳 balance between resistance reduction and crystal defect minimization. This parameter control ensures that the impurity concentration remains within the enhanced solubility limit provided by co-doping without exceeding the threshold that would cause excessive crystal defects.
3Reliability
If deep impurity levels are used in SiC, then the material maintains its intrinsic properties, but resistance cannot be lowered effectively
Solution Approach 1:
The patent changes the electrical properties of SiC by introducing co-doped impurity structures that create shallower effective energy levels. The interaction between p-type and n-type impurities in pair or trimer configurations modifies the band structure and creates more easily ionized states, thereby improving electrical conductivity while maintaining the ability to control device characteristics through impurity ratio optimization.
Solution Approach 2:
The patent makes the impurity doping system more versatile by enabling a wide range of p-type to n-type impurity ratios (0.40 to 0.95) to be used for different device requirements. This multi-functional doping approach allows the same co-doping mechanism to achieve both resistance reduction and various device-specific electrical characteristics, enhancing the adaptability of SiC for different power semiconductor applications.
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 results in reduced sheet resistance, lower resistivity, and increased impurity activation, leading to more efficient power semiconductor devices with improved energization breakdown tolerance and reduced crystal defects, enabling the creation of high-performance MOSFETs and IGBTs.
Implementation Method 1
The implementation of co-doping techniques involving specific combinations of p-type and n-type impurities such as aluminum (Al), gallium (Ga), indium (In), nitrogen (N), boron (B), and phosphorus (P) in SiC, where the concentration ratio of these impurities is optimized between 0.40 and 0.95, forming stable pair or trimer structures that reduce strain and enhance impurity solubility
Implementation Method 2
a p-type impurity and an n-type impurity are implanted to form an n-type SiC region
Data Source
AI summary
A semiconductor device of an embodiment includes an n-type SiC impurity region containing a p-type impurity and an n-type impurity. Where the p-type impurity is an element A and the n-type impurity is an element D, the element A and the element D form a combination of Al (aluminum), Ga (gallium), or In (indium) and N (nitrogen), and/or a combination of B (boron) and P (phosphorus). The ratio of the concentration of the element A to the concentration of the element D in the above combination is higher than 0.40 but lower than 0.95, and the concentration of the element D forming the above combination is not lower than 1×1018 cm−3 and not higher than 1×1022 cm−3.