Trench Gate Semiconductor Structure for Electric Field Suppression
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Solution Overview
Problem
Power semiconductor devices face the challenge of electric field concentration at the boundary of the base region and/or at the bottom of the trench-type gate, which limits their breakdown voltage.
Innovation Solution
A semiconductor device design that includes a substrate with a dummy gate structure and a gate structure, featuring a first well region and a second well region with different valence electron counts, and a source region with a higher atomic concentration. The dummy gate structure is electrically connected through a second interconnection structure, allowing for the application of a negative voltage to reduce electric field concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a trench-type gate structure is used in power semiconductor devices, then the device can achieve better performance, but electric field concentration occurs at the bottom of the trench-type gate and at the boundary of the base region, which limits the breakdown voltage
Solution Approach 1:
A dummy gate structure is formed in advance before the main gate structure, extending from the source region into the first well region. This preliminary structure creates an interface dipole that pre-establishes an electric field distribution that prevents harmful concentration at critical locations when the device operates.
Solution Approach 2:
The dummy gate structure acts as an intermediary element between the source region and the first well region. It mediates the electric field distribution by creating a controlled interface dipole at its boundary with the first well region, thereby preventing direct electric field concentration at the main gate bottom and base region boundary.
2Reliability
If the atomic concentration of the source region is increased to improve conductivity, then the on-resistance decreases, but the electric field concentration at the base region boundary may worsen
Solution Approach 1:
The dummy gate structure serves as a mediator between the high-concentration source region and the first well region. The interface dipole created at the dummy gate boundary controls and distributes the electric field, allowing the source region to have high atomic concentration for low on-resistance without causing excessive electric field concentration at the base region boundary.
Solution Approach 2:
By introducing the dummy gate structure with specific doping characteristics (formed by doping at least one element from a first element group), the electric field distribution parameters are changed. The interface dipole creates a favorable electric field profile that allows high source region doping concentration while maintaining acceptable electric field distribution at the base region boundary.
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
The design effectively suppresses electric field concentration, thereby increasing the breakdown voltage of the semiconductor device and enhancing its reliability.
Implementation Method 1
the phenomenon of electric field concentration is likely to occur at the boundary of the base region (or channel layer) and/or at the bottom of the trench-type gate
Implementation Method 2
An interface dipole is formed between the dummy gate structure and the first well region
Data Source
AI summary
A semiconductor device includes a substrate, a dummy gate structure, and a gate structure. The substrate has a dummy gate trench and a gate trench, and includes a first well region, a second well region and a source region. The first well region is formed by doping at least one element from a first element group, and has a first conductive channel. The second well region is formed by doping at least one element from a second element group, the second well region is on the first well region and has a second conductive channel, a polarity of the second conductive channel is opposite to that of the first conductive channel. The dummy gate structure is in the dummy gate trench of the substrate, and a portion of the dummy gate structure is in the first well region. The gate structure is between the adjacent dummy gate structures.