Cascode Semiconductor Device Withstand Voltage Control
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Solution Overview
Problem
The existing cascode connection technique for power transistors is limited by the withstand voltage of the gate oxide film, leading to increased parasitic resistance and reduced reliability as the number of stages increases, making it difficult to achieve high withstand voltage without compromising gate reliability.
Innovation Solution
A semiconductor device configuration where the first semiconductor element and one or more second semiconductor elements are connected in series, with a control signal output terminal between the source and drain terminals, and the gate terminal of the second semiconductor element connected to the control signal output terminal of the adjacent second semiconductor element, allowing for independent control of each stage and reducing the number of stages needed to achieve a desired withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the number of cascode connection stages is increased to achieve high withstand voltage, then the withstand voltage is improved, but the parasitic resistance increases and reliability is reduced
Solution Approach 1:
The patent introduces a control signal output terminal as an intermediary between the first and second semiconductor elements. This terminal outputs the voltage from the drain of the first element to control the gate of the second element, eliminating the need for direct gate oxide film withstand and reducing the number of series stages required to achieve high overall withstand voltage.
2Strength
If the number of cascode connection stages is increased to achieve high withstand voltage, then the withstand voltage is improved, but the parasitic resistance increases
Solution Approach 1:
By using the control signal output terminal as a mediator to transfer the voltage signal from the first element's drain to the second element's gate, the patent reduces the number of intermediate connection stages needed, thereby minimizing the accumulation of parasitic resistance while maintaining high withstand voltage capability.
Data Source
AI summary
The semiconductor device configures a cascode-type high voltage element comprising a plurality of low voltage elements connected in series, wherein the number of stages of connected low voltage elements is reduced, and the high voltage element has desired withstand voltage, without limiting the withstand voltage of the gate oxide film of the low voltage elements. The semiconductor device comprises a first semiconductor element and one or more second semiconductor elements connected in series, wherein the first and the second semiconductor elements have a control signal output terminal between a source terminal and a drain terminal or between an emitter terminal and a collector terminal; and a gate terminal of the one or more second semiconductor elements is connected to the control signal output terminal of the first or second semiconductor element connected in series adjacently to the source or emitter side of said one or more second semiconductor elements.