Bidirectional Thyristor Electrode Layout for Fast Turn-On
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bidirectional thyristor devices face challenges in achieving short turn-on and turn-off times while maintaining high di/dt capability, with complex process flows and suboptimal electrical parameters, particularly in high-voltage direct-current (HVDC) transmission systems.
Innovation Solution
A bidirectional thyristor device with a semiconductor body featuring segmented main electrodes and gate electrodes that surround segments, forming ohmic contacts and utilizing full wafer area without separation regions, enabling fast turn-on and high surge current capability through increased gate-cathode boundary and interdigitation of anode, cathode, and gate regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two monolithically integrated antiparallel thyristor functions are formed by two separated, individually triggered regions on one wafer, then bidirectional control is achieved, but the electrical parameters dependent on the device area are halved and thermal resistance is doubled
Solution Approach 1:
The patent merges the anode regions of two antiparallel thyristors into a single common anode structure, allowing both thyristor functions to share the same wafer area without separation regions. This merging approach maintains full wafer area utilization for current conduction while enabling bidirectional control, thus preserving electrical parameters and thermal resistance characteristics.
2Speed
If gate electrodes are distributed over the whole main surfaces, then the boundary between gate electrode and cathode is maximized for fast turn-on, but device complexity increases
Solution Approach 1:
The gate electrodes are segmented into multiple regions distributed across the main surfaces, with each segment surrounding specific cathode segments. This segmentation maximizes the gate-cathode boundary area for fast turn-on and high di/dt capability while maintaining a manageable structural complexity through systematic arrangement.
Solution Approach 2:
The gate electrodes are configured to completely surround segments of the associated main electrode in a nested arrangement, where the gate electrode structure encloses the cathode segments. This nesting approach maximizes the gate-cathode interface area for rapid turn-on while organizing the complexity in a structured manner.
3Loss of time
If a common p-n-p region is used for both antiparallel p-n-p-n sections, then short commutation turn-off times are achieved, but turn-on time and di/dt capability are compromised
Solution Approach 1:
The patent implements different structural characteristics in different regions: the base layers are optimized for fast turn-off with appropriate doping and thickness, while the emitter regions and gate-cathode boundaries are specifically designed to maximize turn-on speed and di/dt capability. This local optimization allows simultaneous achievement of fast turn-off and fast turn-on characteristics.
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 1E~1F
AI summary
A bidirectional thyristor device (1) comprising a semiconductor body (2) extending between a first main surface (21) and a second main surface (22), is provided wherein a first main electrode (31) and a first gate electrode (41) are arranged on the first main surface and a second main electrode (32) and a second gate electrode (42) are arranged on the second main surface. The first main electrode comprises a plurality of first segments (310) that are spaced apart from one another, wherein at least some of the first segments are completely surrounded by the first gate electrode in a view onto the first main surface. The second main electrode comprises a plurality of second segments (320) that are spaced apart from one another, wherein at least some of the second segments are completely surrounded by the second gate electrode in a view onto the second main surface. The gate may have a honeycomb (hexagon) pattern. The bidirectional thyristor device (1) further comprises first, second and third base regions (51, 52, 53), as well as emitter regions (61, 62) on either side of the base regions. The emitter regions (61, 62) comprise emitter short regions (71, 72) of the opposite conductivity type.