SiC Trench Gate Deep-Layer Structure for Electric Field Relaxation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In silicon carbide (SiC) semiconductor devices with trench gate structures, dielectric breakdown of the gate insulating film occurs due to high electric field stress, leading to reduced gate life, increased on-resistance, and voltage fluctuations.
Innovation Solution
The semiconductor device incorporates a trench gate structure with a first deep layer having a stripe portion and a frame-shaped portion in both active and inactive regions, where the width of the end portion of each line is equal to or greater than the inner portion, and a second deep layer with wider end portions to suppress electric field rise and enhance electric field relaxation, thereby reducing on-resistance and voltage fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a trench gate structure with high channel density is adopted to allow large current, then the current capacity is improved, but dielectric breakdown of the gate insulating film occurs due to high electric field stress
Solution Approach 1:
The patent applies local quality by creating a non-uniform impurity concentration distribution in the drift layer, with higher impurity concentration near the trench gate structure and lower concentration farther away. This localized variation in electrical properties allows the region near the trench to have higher conductivity (reducing electric field stress) while maintaining lower conductivity in other regions for voltage blocking capability.
Solution Approach 2:
The patent changes the impurity concentration parameter of the drift layer from uniform to non-uniform distribution. By controlling the impurity concentration to be higher near the trench gate structure and lower in other regions, the electrical characteristics are optimized to reduce electric field stress on the gate insulating film while maintaining voltage blocking capability.
2Productivity
If the trench gate structure is used to increase channel density, then the switching element performance is improved, but the gate life is reduced due to electric field stress
Solution Approach 1:
The patent applies local quality by creating a non-uniform impurity concentration distribution in the drift layer, with higher impurity concentration near the trench gate structure and lower concentration farther away. This localized variation in electrical properties allows the region near the trench to have higher conductivity (reducing electric field stress) while maintaining lower conductivity in other regions for voltage blocking capability.
Solution Approach 2:
The patent changes the impurity concentration parameter of the drift layer from uniform to non-uniform distribution. By controlling the impurity concentration to be higher near the trench gate structure and lower in other regions, the electrical characteristics are optimized to reduce electric field stress on the gate insulating film while maintaining voltage blocking capability.
3Loss of energy
If the impurity concentration in the drift layer is increased to reduce on-resistance, then the conductivity is improved, but the voltage blocking capability is reduced
Solution Approach 1:
The patent applies local quality by creating a non-uniform impurity concentration distribution in the drift layer, with higher impurity concentration near the trench gate structure and lower concentration farther away. This localized variation in electrical properties allows the region near the trench to have higher conductivity (reducing electric field stress) while maintaining lower conductivity in other regions for voltage blocking capability.
Solution Approach 2:
The patent changes the impurity concentration parameter of the drift layer from uniform to non-uniform distribution. By controlling the impurity concentration to be higher near the trench gate structure and lower in other regions, the electrical characteristics are optimized to reduce electric field stress on the gate insulating film while maintaining voltage blocking capability.
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 effectively suppresses dielectric breakdown, maintains gate life, and reduces on-resistance and forward voltage fluctuations by restricting high electric fields and promoting efficient carrier recombination.
Implementation Method 1
promoting efficient carrier recombination
Data Source
AI summary
A semiconductor device includes a second deep layer between a first deep layer and first current distribution layer and a base region in an active region and in a part of an inactive region adjacent to the active region. The second deep layer has a second stripe portion including lines connecting to the base region and the first deep layer. The semiconductor device further includes a second current distribution layer between the first current distribution layer and the base region and arranged between the lines of the second stripe portion. The first deep layer has a first stripe portion including a plurality of lines, and each line has an end portion connecting to a frame-shaped portion and an inner portion on an inner side of the end portion. The width of the end portion is equal to or greater than the inner portion.