SiC Superjunction Doping Feedback for Voltage Blocking Control
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Solution Overview
Problem
There is a need to precisely adjust the ratio of dopant atoms in silicon carbide (SiC) superjunction devices to enhance their voltage blocking capability without causing Avalanche breakdown, as existing methods lack precision in controlling the doping process.
Innovation Solution
A method involving measuring characteristics of the superjunction region and adjusting doping process parameters, such as implantation dose and annealing temperature, to generate dopant-like defects that refine the dopant ratio, thereby optimizing the voltage blocking capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional doping methods are used to dope the superjunction region, then the doping process can be completed, but the dopant ratio cannot be precisely controlled leading to insufficient voltage blocking capability
Solution Approach 1:
The patent employs a feedback mechanism where the doping process parameters (such as ion implantation dose, energy, and annealing conditions) are adjusted based on measured characteristics of the superjunction region. This closed-loop control enables precise control of the dopant ratio by continuously monitoring and correcting the doping process, thereby achieving the desired voltage blocking capability without Avalanche breakdown.
Solution Approach 2:
The patent utilizes parameter changes in the doping process, specifically adjusting ion implantation parameters (dose, energy, angle) and thermal annealing parameters (temperature, time, atmosphere) to precisely control the dopant ratio. By varying these parameters systematically, the method achieves fine-tuned control over the electrical characteristics of the superjunction region, resolving the contradiction between manufacturing precision and device reliability.
2Reliability
If the dopant ratio is not precisely adjusted, then the manufacturing process is simpler, but the voltage blocking capability is insufficient and Avalanche breakdown occurs
Solution Approach 1:
The patent applies preliminary action by performing ion implantation to create crystal defects and dopant-like defects before the final annealing step. This preliminary defect creation allows subsequent annealing processes to precisely control the dopant activation and distribution, achieving the desired dopant ratio with better control. The preliminary implantation step sets the foundation for precise subsequent processing, resolving the contradiction between reliability and complexity.
Solution Approach 2:
The patent uses crystal defects and dopant-like defects as intermediaries between the ion implantation process and the final doping configuration. These intermediate defect structures serve as precursors that can be precisely controlled through annealing, allowing indirect but precise control of the final dopant distribution. This intermediary approach enables better control over the dopant ratio while managing process complexity.
3Manufacturing precision
If ion implantation is used to create crystal defects, then dopant-like defects can be formed, but the process requires precise parameter adjustment increasing manufacturing complexity
Solution Approach 1:
The patent employs self-service by utilizing the ion implantation process to automatically create crystal defects and dopant-like defects that then guide subsequent annealing processes. The implanted ions serve their dual purpose of both creating the desired defect structure and providing a template for the final dopant configuration. This self-organizing approach reduces the need for multiple separate processing steps, improving ease of manufacture while maintaining high precision.
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 method effectively increases the voltage blocking capability of SiC superjunction devices by precisely adjusting the dopant ratio, reducing the steepness of the electric field and enhancing the device's ability to withstand critical voltages without breakdown.
Implementation Method 1
The doping process includes an implantation process in which particles are implanted into the semiconductor body to form crystal defects in the semiconductor body in the superjunction region
Implementation Method 2
an annealing process in order to form the dopant like defects based on the crystal defects
Implementation Method 3
an Avalanche breakdown may occur when a voltage that reverse biases the pn-junctions between the first and second regions is such that a magnitude of the electric field reaches a critical value
Data Source
AI summary
Disclosed is a method that includes: measuring at least one characteristic of a superjunction region of a SiC superjunction device, wherein the superjunction region is arranged in a semiconductor body and comprises a plurality of first regions of a first doping type and a plurality of second regions of a second doping type complementary to the first doping type; and generating dopant like defects of one doping type in the superjunction region in a doping process. At least one parameter of the doping process is adjusted dependent on the at least one measured characteristic. The doping process includes an implantation process in which particles are implanted into the semiconductor body to form crystal defects in the semiconductor body in the superjunction region, and an annealing process in order to form the dopant like defects based on the crystal defects.