Trench MOSFET Latch-Up Prevention via Segmented Insulation
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Solution Overview
Problem
Integrated electronic devices such as MOSFETs and IGBTs are prone to the latch-up phenomenon, where a self-sustaining current path forms, preventing switching off and causing operational issues due to parasitic transistors.
Innovation Solution
A vertical conduction integrated electronic device is designed with a trench MOSFET structure that eliminates the parasitic NPN transistor by using a conductive source region and a gate region with a cusp-shaped profile, ensuring no parasitic NPN transistor is present, thus preventing latch-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional vertical conduction integrated electronic device structure is used, then high current conduction and high voltage withstand capability are achieved, but the device is susceptible to latch-up phenomenon caused by parasitic transistors
Solution Approach 1:
The device structure is segmented by introducing a trench that divides the semiconductor body into distinct regions. The trench contains an insulation region that physically separates the gate region from the body region, thereby eliminating the parasitic NPN transistor path and preventing latch-up while maintaining the high voltage and high current capabilities of the vertical conduction structure
Solution Approach 2:
An insulation region is introduced as an intermediary element between the gate region and the body region within the trench. This insulation region acts as a mediator that blocks the formation of parasitic transistor paths while allowing the device to maintain its functional performance for high voltage and high current operation
2Reliability
If insulation regions are added to prevent latch-up, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The trench structure and insulation region are formed during the preliminary stages of device fabrication, before the active transistor regions are fully developed. By preparing the trench and insulation structure in advance, the subsequent formation of source and drain regions can proceed without additional complex steps, thereby improving ease of manufacture while maintaining latch-up protection
Data Source
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AI summary
A vertical conduction integrated electronic device including: a semiconductor body (12); a trench (22) that extends through part of the semiconductor body and delimits a portion (24) of the semiconductor body, which comprises a first conduction region (16) having a first type of conductivity and a body region (40) having a second type of conductivity, which overlies the first conduction region; a gate region (30) of conductive material, which extends within the trench; an insulation region (39a) of dielectric material, which extends within the trench and is arranged between the gate region and the body region; and a second conduction region (20), which overlies the body region. The second conduction region is formed by a conductor.