SiC Trench Semiconductor Structure for Gate Dielectric Shielding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor components face challenges in achieving a balance between low on-resistance and high dielectric strength, particularly in power semiconductor switches like MOSFETs and IGBTs, where the breakdown strength of the gate dielectric limits the voltage rating due to high electric fields in the off-state.
Innovation Solution
A method involving a silicon carbide substrate with trenches and a shielding region formed along the trench bottom, where the dopant concentration varies by no more than 10% in a specific width, creating a uniform dopant plateau to shield the gate dielectric from high electric fields, thereby enhancing the breakdown strength without increasing on-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the vertical extent of the drift zone is increased to improve dielectric strength, then the breakdown strength is improved, but the on resistance increases
Solution Approach 1:
The patent applies local quality by creating a shielding region with specific dopant concentration characteristics (deviating by not more than 10% from maximum value over at least 30% of trench width) localized at the trench bottom. This localized doping structure shields the gate dielectric from high electric fields in the off-state, allowing the drift zone to be optimized for dielectric strength without compromising on-resistance, as the shielding region locally manages the electric field distribution.
2Strength
If a shielding region with uniform dopant concentration is formed to protect the gate dielectric, then the breakdown strength is improved, but the device complexity increases
Solution Approach 1:
The patent employs parameter changes by precisely controlling the dopant concentration parameter in the shielding region. The dopant concentration deviates by not more than 10% from the maximum value over a lateral width of at least 30% of the trench width, creating a controlled parameter variation that achieves effective shielding. This parameter control approach enhances breakdown strength while maintaining manufacturing feasibility through standardized doping processes.
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 solution effectively increases the breakdown strength of the gate dielectric, reducing the probability of breakdown and enhancing the reliability of semiconductor components while maintaining low on-resistance.
Implementation Method 1
the gate dielectric is exposed to a strong electric field in off-state case
Implementation Method 2
a dopant concentration in the shielding region over a lateral first width deviates by not more than 10% from a maximum value of the dopant concentration in the shielding region
Data Source
AI summary
A semiconductor component includes: a SiC semiconductor body; a trench extending from a first surface of the SiC semiconductor body into the SiC semiconductor body, the trench having a conductive connection structure, a structure width at a bottom of the trench, and a dielectric layer covering sidewalls of the trench; a shielding region along the bottom and having a central section which has a lateral first width; and a contact formed between the conductive connection structure and the shielding region. The conductive connection structure is electrically connected to a source electrode. In at least one doping plane extending approximately parallel to the bottom, a dopant concentration in the central section deviates by not more than 10% from a maximum value of the dopant concentration in the shielding region in the doping plane. The first width is less than the structure width and is at least 30% of the structure width.