Segmented Bidirectional Thyristor Layout for Fast Switching
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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 electrical parameters being halved in antiparallel connected thyristors.
Innovation Solution
A bidirectional thyristor device design featuring a semiconductor body with segmented main electrodes and gate electrodes that surround the segments, forming an ohmic contact and utilizing full wafer area, allowing for fast turn-on and turn-off capabilities with enhanced di/dt and dV/dt capabilities, and incorporating an amplifying gate structure for homogeneous turn-on.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two separated individually triggered regions are formed on one wafer to create bidirectional control thyristor, then bidirectional control capability is achieved, but the surge current is halved and thermal resistance is doubled
Solution Approach 1:
The device segments the thyristor structure into two antiparallel-connected thyristor functions (first and second thyristor functional elements) that share a common p-n-p region. This segmentation enables bidirectional control capability while maintaining full wafer utilization for each thyristor function, thereby preserving high surge current capability despite the bidirectional requirement
2Speed
If gate electrodes are distributed over the whole main surfaces to maximize gate-cathode boundary, then turn-on time is reduced and di/dt capability is enhanced, but device complexity increases
Solution Approach 1:
The gate electrodes serve multiple functions simultaneously: they provide triggering control for their respective thyristor functional elements, maximize the gate-cathode boundary area for fast turn-on, and are distributed across the entire main surfaces to enhance di/dt capability. This multi-functionality achieves superior performance without proportionally increasing device complexity
3Loss of time
If common p-n-p region is used for both antiparallel p-n-p-n sections, then commutation turn-off times are shortened, but turn-on time and di/dt capability are compromised
Solution Approach 1:
The device implements local quality optimization by providing separate emitter regions and emitter short regions for each thyristor functional element, while sharing the common p-n-p region. This allows the turn-off performance to benefit from the common structure while the turn-on performance is enhanced by the locally optimized gate-cathode boundaries and distributed gate electrodes
Data Source
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.