Insulating Trench TRIAC Structure for Noise-Immune Triggering
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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 is introduced in the semiconductor design, bisecting the N+ regions, P regions, and N- region, creating two operational halves that improve noise immunity and performance by eliminating shunt current and enhancing static dv/dt and commutating performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional 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 thyristors. The insulating trench physically separates the two thyristor structures, isolating their respective gate regions. This segmentation prevents noise from affecting both thyristors simultaneously and allows independent gate control, thereby improving noise immunity while maintaining bidirectional current control capability.
Solution Approach 2:
An insulating trench is introduced as an intermediary element between the two thyristor structures. This trench, filled with insulating material, acts as a barrier that blocks noise coupling between the thyristors while maintaining electrical isolation. The intermediary structure enables the device to achieve high noise immunity without sacrificing the bidirectional switching function.
2Ease of operation
If the gate terminal is made very sensitive to activate the device, then the device can be easily triggered, but the device becomes susceptible to noise causing mis-triggering
Solution Approach 1:
The single gate terminal is segmented into two independent gate terminals (G1 and G2), each associated with a separate thyristor structure. This segmentation allows each gate to be optimized for its specific thyristor, maintaining high sensitivity for intended triggering while the physical separation through the insulating trench prevents noise from causing unintended triggering of either thyristor.
3Reliability
If a trench is introduced to improve noise immunity, then noise sensitivity is reduced, but the device complexity increases
Solution Approach 1:
The insulating trench is introduced by removing material from the semiconductor substrate, extracting a portion of the continuous structure to create isolated regions. This extraction approach achieves noise immunity by physically separating the thyristor structures while maintaining a relatively simple overall device architecture, as the trench formation is a straightforward fabrication process.
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2A
AI summary
A TRIAC semiconductor includes an N- region (310), multiple N+ regions (314a-e), and a trench (326). The N- region (310) is sandwiched between two P regions (308, 312). The first P region (308) is connected to an MT2 terminal and the second P region (312) is connected to two MT1 terminals. The multiple N+ regions are located within the first P region (312). The trench (326) is located between two gate terminals (G).