SiC Trench MOSFET Super Junction for Short-Circuit Resistance
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Solution Overview
Problem
Existing semiconductor devices, particularly MOSFETs, face challenges in improving short circuit resistance, which is critical for reliability and preventing heat-related failures during high current flows, due to limitations in trench gate structures and impurity concentration distributions.
Innovation Solution
The semiconductor device incorporates a trench gate structure with specific impurity concentration gradients and regions in a silicon carbide layer, including n-type and p-type control regions, to manage current flow and heat generation effectively, enhancing short circuit resistance by altering the current path and reducing on-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a trench gate structure is applied to increase channel area and reduce on-resistance, then the on-resistance is reduced, but the short circuit resistance deteriorates due to rapid breakdown when short circuit occurs
Solution Approach 1:
The semiconductor device divides the semiconductor layer into multiple alternating n-type and p-type regions, creating a segmented super junction structure. This segmentation allows the device to achieve both low on-resistance through increased channel area and high short circuit resistance through the depletion of oppositely doped regions that block current flow during short circuit conditions
Solution Approach 2:
The patent applies different doping types (n-type and p-type) to different local regions of the semiconductor layer, creating regions with different electrical properties. The n-type regions provide high electron concentration for low on-resistance, while the alternating p-type regions create depletion zones that improve short circuit resistance by blocking current during fault conditions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration improves short circuit resistance by redirecting heat generation to deeper layers, reducing the risk of electrode melting and maintaining device reliability under high current conditions, while also minimizing on-resistance and off-leakage currents.
Implementation Method 1
achieves high breakdown voltage and low on-resistance, enhancing the device's reliability and resistance to short circuits by depleting p-type and n-type semiconductor regions
Implementation Method 2
allowing current to flow through high impurity concentration regions
Data Source
AI summary
A semiconductor device of an embodiment includes a trench in a silicon carbide layer and extending in a first direction, a gate electrode in the trench, first, second, third and fourth silicon carbide regions disposed in the silicon carbide layer in the first direction in this order, first and third silicon carbide regions having first conductive type, second and fourth silicon carbide regions having second conductive type, fifth, sixth, seventh and eighth silicon carbide regions disposed in the silicon carbide layer in the first direction in this order above the first to fourth silicon carbide regions, fifth and seventh silicon carbide regions having first conductive type higher than first and third silicon carbide regions, sixth and eighth silicon carbide regions having second conductive type higher than second and fourth silicon carbide regions, a ninth silicon carbide region of a first conductive type above the fifth to eighth silicon carbide regions.