Trench Gate IGBT Floating P-Type Layers ESD Noise
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Solution Overview
Problem
Trench gate IGBTs face challenges with reduced input capacitance and decreased ESD tolerance due to smaller gate trench occupancy, particularly in small current applications, leading to noise sensitivity and reduced robustness.
Innovation Solution
The design incorporates two floating P-type layers with two emitter trenches and at least two gate trenches disposed between them, forming an EGGE structure that increases gate trench occupancy, enhancing noise and ESD tolerance while maintaining reduced feedback capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gate trench occupancy is reduced to improve switch characteristics, then feedback capacitance is reduced, but input capacitance decreases and ESD tolerance decreases
Solution Approach 1:
The patent divides the gate structure into multiple gate trenches (first gate trench and second gate trench) separated by an emitter trench, rather than using a single continuous gate trench. This segmentation allows the gate to occupy a larger total area while maintaining reduced feedback capacitance through the interrupted structure, thereby improving ESD tolerance without sacrificing switch characteristics.
Solution Approach 2:
The patent embeds the emitter trench within the gate structure by positioning it between the first and second gate trenches. This nested arrangement allows the emitter trench to be integrated into the gate region, enabling the gate trenches to extend further and increase gate trench occupancy while the emitter trench provides functional separation that maintains low feedback capacitance.
2Object-affected harmful factors
If gate trench occupancy is reduced to improve switch characteristics, then feedback capacitance is reduced, but noise tolerance decreases
Solution Approach 1:
By segmenting the gate into multiple trenches with an emitter trench in between, the patent increases the total gate trench occupancy area. This larger area improves noise tolerance by providing better signal coupling and reduced susceptibility to external noise, while the segmented structure maintains the low feedback capacitance needed for good switch characteristics.
3Reliability
If emitter trench depth is increased to improve carrier storage, then collector-emitter voltage is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent segments the deep trench structure into multiple shallower trenches (first gate trench, emitter trench, second gate trench) rather than requiring a single extremely deep trench. This segmentation reduces the etching depth requirement for each individual trench, making manufacturing more precise and reliable while still achieving the necessary carrier storage effect through the combined depth and structure of all trenches.
Data Source
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AI summary
A high-performance trench gate IGBT is provided. A trench gate IGBT according to one embodiment includes: a semiconductor substrate (11); a channel layer (15) provided on the semiconductor substrate (11); two floating P-type layer (12) provided on both sides of the channel layer 15, the floating P-type layers (12) being deeper than the channel layer (15); two emitter trenches (13) disposed between the two floating P-type layers (12), the emitter trenches (13) being respectively in contact with the floating P-type layers (12); at least two gate trenches (14) disposed between the two emitter trenches (13); and a source diffusion layer (19) disposed between the two gate trenches 14, the source diffusion layer (19) being in contact with each of the gate trenches (14).