IGBT Diode Trench Gate Withstand Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing semiconductor device with a trench gate structure in both IGBT and diode faces challenges in securing a sufficiently high withstand voltage due to the inability of the depletion layer to extend smoothly between the trench gates, leading to potential electric field concentration and reduced voltage endurance.
Innovation Solution
The semiconductor device incorporates a design where the trench gates in the IGBT and diode are insulated from each other, with specific stripe and annular portions arranged to maintain a consistent distance, and optionally includes a p-well layer to cover the end portions of the trench gates, ensuring the depletion layer can extend effectively and reducing electric field concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the trench gate in the diode is electrically insulated from the trench gate in the IGBT, then the gate capacitance is reduced, but the depletion layer cannot extend smoothly in the substrate depth direction and a sufficiently high withstand voltage cannot be secured
Solution Approach 1:
A p-type well layer is introduced as an intermediary structure between the IGBT trench gate and diode trench gate. This p-type well layer serves as a mediator that enables the depletion layer to extend smoothly from the IGBT region into the diode region, ensuring high withstand voltage capability while maintaining the electrical insulation between the two trench gates for reduced gate capacitance.
Solution Approach 2:
The p-type well layer is selectively formed only in the region between the IGBT trench gate and diode trench gate, creating a localized structural modification. This local quality change allows the depletion layer to extend smoothly in the specific critical region without affecting other areas of the device, resolving the contradiction between insulation and voltage withstand.
2Reliability
If the trench gate structure is used in both IGBT and diode, then the withstand voltage with respect to Vce voltage is increased, but the depletion layer extension is interrupted and electric field concentration occurs
Solution Approach 1:
The p-type well layer acts as an intermediary that bridges the gap in depletion layer extension caused by the trench gate structure. It provides a continuous path for the depletion layer to extend from the IGBT region through the interface region into the diode region, preventing electric field concentration at the trench gate boundaries while maintaining the 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 secures a sufficiently high withstand voltage while reducing gate capacitance, preventing electric field concentration and maintaining stability, thus enhancing the semiconductor device's performance.
Implementation Method 1
the depletion layer cannot extend smoothly in the substrate depth direction between the trench gate in the IGBT and the trench gate in the diode
Implementation Method 2
The gate capacitance can be reduced by electrically insulating the trench gate in the diode from the trench gate in the IGBT
Data Source
AI summary
A semiconductor device is configured such that the distance between the trench gate in the IGBT and the trench gate in the diode is reduced or a p-well layer is provided between the trench gate in the IGBT and the trench gate in the diode.