Trench IGBT Structure With Added Capacitance for Lower Turn-On Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices with Insulated Gate Bipolar Transistors (IGBTs) face challenges in reducing turn-on loss, which affects their efficiency and performance.
Innovation Solution
The semiconductor device incorporates a semiconductor substrate with a drift region, an emitter region with higher doping concentration, a base region of opposite conductivity type, and a first accumulation region with higher doping concentration than the drift region. Additionally, it features trench portions that pass through these regions and include a conductive portion, along with a capacitance addition portion below the first accumulation region to enhance gate-collector capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional IGBT structures are used, then device simplicity is maintained, but turn-on loss increases
Solution Approach 1:
The drift region is segmented into multiple regions with different doping concentrations: a first drift region, a second drift region with higher doping concentration, and a third drift region with even higher doping concentration. This segmentation allows optimization of turn-on loss by creating favorable electric field distribution while maintaining manageable structural complexity through systematic regional division.
Solution Approach 2:
Different regions of the drift region are assigned different doping concentrations to achieve local optimization. The second drift region has higher doping concentration than the first, and the third drift region has higher doping concentration than the second. This local quality variation reduces turn-on loss by controlling carrier injection and electric field distribution in specific areas without requiring complete structural redesign.
2Loss of energy
If doping concentration in drift region is increased, then turn-on loss is reduced, but breakdown voltage decreases
Solution Approach 1:
The drift region is divided into three segments with progressively increasing doping concentrations from the first to the third drift region. This segmentation enables the device to achieve low turn-on loss in regions with higher doping while maintaining adequate breakdown voltage through the combined effect of all regions, as each region contributes differently to both parameters.
Solution Approach 2:
The doping concentration parameter is changed progressively across different drift regions rather than being uniform. The second drift region has higher doping concentration than the first, and the third has higher than the second. This parameter change strategy optimizes the trade-off between turn-on loss and breakdown voltage by creating favorable carrier distribution and electric field profiles.
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 reduces turn-on loss while maintaining a balance between ON voltage and turn-off loss, thereby enhancing the overall performance and efficiency of the semiconductor device.
Implementation Method 1
a first accumulation region of a first conductivity type provided between the base region and the drift region inside the semiconductor substrate and having a doping concentration higher than the drift region
Implementation Method 2
a capacitance addition portion provided below the first accumulation region to add a gate-collector capacitance thereto
Data Source
AI summary
A semiconductor device includes a first region in which a drift, base, and accumulation regions are stacked. Transistor cells are each provided partially in the first region and include at least one trench extending into the drift region. A second region includes a well region provided on an edge termination region side surrounding the first region. A third region of a predetermined width is between the first and second regions, inside of which the transistor cells are partially provided. A bottom region is provided in the first region, adjacent to a bottom of the trench, and between the accumulation and drift regions, the bottom region not extending into the third region, its upper surface located below the base region's lower surface; and first and second electrodes configured to flow current therebetween. The bottom region is spaced apart from the base region by the accumulation region in the depth direction.