Dual-Gate Trench TRIAC Layout for Noise Immunity
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Solution Overview
Problem
TRIACs are sensitive to noise, leading to mis-triggering and circuit malfunctions due to their susceptibility to small current fluctuations, which affects their reliability in controlling alternating current.
Innovation Solution
A trench-based design is introduced in the TRIAC semiconductor, bisecting the semiconductor into two halves that operate based on the bias of the MT2 and MT1 terminals, eliminating shunt current and improving noise immunity and performance by enhancing static dv/dt and commutating performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional TRIAC structure is used, then the device can control alternating current in both directions, but the device is highly sensitive to noise causing mis-triggering
Solution Approach 1:
The gate terminal is divided into two separate gate terminals (G1 and G2), each controlling one of the two inverse-parallel thyristors. This segmentation isolates the triggering paths, preventing noise from affecting both thyristors simultaneously and reducing mis-triggering susceptibility
Solution Approach 2:
A trench structure is introduced to physically separate and isolate the two thyristor structures within the semiconductor device. This extraction of the separating element (trench) eliminates parasitic coupling paths and shunt currents that cause noise sensitivity
2Ease of operation
If the gate terminal is made highly sensitive to enable easy triggering, then the device can be activated with very small current, but the device becomes susceptible to noise-induced mis-triggering
Solution Approach 1:
By dividing the single gate terminal into two separate gate terminals (G1 and G2), each gate controls its respective thyristor independently. This allows maintaining high sensitivity for intended triggering while preventing noise from activating both thyristors unintentionally, as the trench isolation blocks noise coupling paths
3Reliability
If a trench structure is introduced to improve noise immunity, then noise sensitivity is reduced, but the device complexity increases
Solution Approach 1:
The trench structure introduces a vertical dimensional separation between the two thyristor structures, cutting through the semiconductor layers to create physical isolation. This dimensional approach to isolation is more effective than lateral separation alone, achieving noise immunity with a compact design that integrates well within the device footprint
Data Source
AI summary
A TRIAC semiconductor includes an N− region, multiple N+ regions, and a trench. The N− region is sandwiched between two P regions. The first P region is connected to an MT2 terminal and the second P region is connected to two MT1 terminals. The multiple N+ regions are located within the first P region. The trench is located between two gate terminals.