SiC Diode Series String for High Voltage Rectification
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Solution Overview
Problem
Conventional silicon-based high voltage diodes fail at elevated temperatures due to reverse bias current conduction, leading to thermal runaway, and have limitations in high voltage hold-off and radiation hardness, making them unsuitable for high temperature and radiation-exposed applications like particle accelerators in hydrocarbon resource wells.
Innovation Solution
The use of silicon carbide (SiC) diode dies connected in series on an elongated dielectric substrate with conductive pads and internal wirebonds, along with external leads, forms a high temperature and high voltage rectifier diode configuration that enhances mechanical integrity, heat dissipation, and radiation hardness, while avoiding shorting and thermal issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional silicon-based high voltage diodes are used, then the device structure is simple and manufacturing is easy, but the diodes fail at elevated temperatures due to reverse bias current conduction leading to thermal runaway
Solution Approach 1:
The patent changes the material parameter from conventional silicon to silicon carbide (SiC), which fundamentally alters the temperature-dependent electrical characteristics. SiC maintains high breakdown voltage and low reverse leakage current at elevated temperatures, preventing thermal runaway while enabling operation beyond 200°C
Solution Approach 2:
The invention uses composite construction by stacking multiple SiC diode dies in series on a common substrate, combining the advantages of SiC material properties with a modular architecture that enhances both temperature resistance and voltage handling capability
2Stress or pressure
If conventional silicon diodes are used, then the device complexity is low, but the high voltage hold-off capability is limited
Solution Approach 1:
The high voltage diode is segmented into multiple individual SiC diode dies connected in series, with each die handling a portion of the total voltage. This segmentation allows the device to achieve ultra-high voltage hold-off capability (10kV and above) while maintaining modular construction that simplifies manufacturing and testing
Solution Approach 2:
Multiple SiC diode dies are merged into a single integrated package with common cathode or anode connections, combining their voltage blocking capabilities while sharing common electrical terminals, thus achieving high voltage hold-off without proportionally increasing external connection complexity
3Object-affected harmful factors
If conventional silicon diodes are used, then the manufacturing process is simple, but the radiation hardness is insufficient for particle accelerator applications
Solution Approach 1:
The patent changes the material composition from silicon to silicon carbide, which inherently provides superior radiation hardness due to SiC's wider bandgap and more robust crystal structure. This material parameter change enables the device to withstand high-radiation environments in particle accelerators while maintaining electrical performance
4Stress or pressure
If multiple SiC diode dies are connected in series, then the voltage hold-off capability increases, but the device size increases
Solution Approach 1:
Multiple SiC diode dies are merged into a compact series string configuration mounted on a common substrate, sharing common electrical connections and minimizing inter-die spacing. This merging approach achieves ultra-high voltage hold-off capability while maintaining a compact device footprint suitable for space-constrained 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
The SiC diode configuration provides a reliable high voltage rectification capability beyond the limitations of silicon diodes, with improved thermal endurance, radiation hardness, and reduced probability of high voltage leakage, enabling more compact and efficient high voltage power supplies for applications like particle accelerators.
Implementation Method 1
Each SiC die having bottom and top diode terminals and being mounted on a respective conductive pad with the bottom diode terminal in electrical contact therewith
Implementation Method 2
at least one internal wirebond between the corresponding conductive pad of one SiC diode die and the top diode terminal of a next SiC diode die
Implementation Method 3
an elongated dielectric substrate having opposing first and second ends, a plurality of conductive pads longitudinally spaced apart along at least one surface of the elongated dielectric substrate
Data Source
AI summary
An electronic device may include an elongated dielectric substrate having opposing first and second ends, a plurality of conductive pads longitudinally spaced apart along the elongated dielectric substrate, and a plurality of silicon carbide (SiC) (e.g., PiN) diode dies. Each SiC die may have bottom and top diode terminals and may be mounted on a respective conductive pad with the bottom diode terminal in contact therewith. The electronic device may further include at least one internal wirebond between the corresponding conductive pad of one SiC diode die and the top diode terminal of a next SiC diode die, a first external lead electrically coupled to the top diode terminal of a first SiC die and extending longitudinally outwardly from the first end, and a second external lead electrically coupled to the corresponding contact pad of a last SiC diode die and extending longitudinally outwardly from the second end.