IEGT Floating Region Reduces Gate Capacitance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power semiconductor devices face challenges in maintaining breakdown voltage while reducing gate capacitance, leading to increased energy consumption and decreased switching functionality.
Innovation Solution
A power semiconductor device with a trench gate structure and a floating region of lower impurity concentration, surrounded by a trench gate structure, which separates the floating region from the base region and includes a deep-well region connected to the emitter electrode, effectively reducing gate capacitance and maintaining breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the floating space of an IEGT is minimized or the resistivity value of an epi layer is increased to obtain breakdown voltage, then the breakdown voltage is improved, but the floating effect decreases and the switching function is reduced
Solution Approach 1:
The patent introduces a floating region with specific impurity concentration (lower than base region) located at a specific position (exterior region of trench gate structure, deeper than trench gate structure) to create local electrical characteristics that differ from surrounding regions. This local quality modification allows the floating region to maintain breakdown voltage while preserving switching function through controlled charge distribution.
Solution Approach 2:
The patent adds a depth dimension to the floating region structure by positioning it deeper than the trench gate structure, creating a three-dimensional charge distribution. This dimensional approach allows the floating region to influence the electric field in the drift region without directly interfering with the surface-level switching operations, thus resolving the contradiction between breakdown voltage and switching function.
2Use of energy by moving object
If gate capacitance is reduced to lower energy consumption, then energy efficiency is improved, but breakdown voltage maintenance becomes difficult
Solution Approach 1:
The floating region acts as an intermediary between the gate structure and the drift region, mediating the electric field distribution. By introducing this intermediate charge layer with controlled impurity concentration, the patent reduces the direct capacitive coupling between gate and drift region (lowering gate capacitance and energy consumption) while still maintaining the necessary breakdown voltage through the floating region's charge distribution.
3Reliability
If the epi layer thickness is increased to improve breakdown voltage, then reliability is improved, but the floating effect decreases and switching function is reduced
Solution Approach 1:
Instead of uniformly increasing epi layer thickness throughout the device, the patent introduces a localized floating region with specific impurity concentration at a specific depth. This local modification achieves the desired electrical characteristics for breakdown voltage without the need for increased overall epi layer thickness, thereby preserving the floating effect and switching function.
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 results in reduced energy consumption and improved switching functionality by maintaining breakdown voltage while minimizing gate capacitance, enhancing the overall performance of the power semiconductor device.
Implementation Method 1
a floating region located on an exterior region of the trench gate structure that surrounds the trench gate structure and is deeper than the trench gate structure, wherein the floating region is electrically floating and surrounds a bottom surface of the trench gate structure
Implementation Method 2
a drift region located on the substrate having a first conductivity type, a base region located under the emitter contact region having a second conductivity type
Data Source
AI summary
The present examples relate to a power semiconductor device. The present examples also relate to a power semiconductor device that maintains a breakdown voltage and reduces a gate capacitance through improving the structure of an Injection Enhanced Gate Transistor (IEGT), and thereby reduces strength of an electric field compared to alternative technologies. Accordingly, the present examples provide a power semiconductor device with a small energy consumption and with an improved switching functionality.