IGBT Stabilizing Plate Insulating Layer Reduces ON Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High ON voltage and short-circuit issues in trench gate type IGBTs due to increased gate capacitance, leading to oscillation and potential breakdown during short-circuiting, which conventional methods fail to adequately address with increased dummy trenches.
Innovation Solution
A semiconductor device design featuring first and second insulated gate field effect transistor portions, a stabilizing plate portion, and an emitter electrode, where the emitter electrode is connected to both transistor portions and stabilizing plates with an insulating layer, reducing current flow through the stabilizing plate and concentrating it in the transistor portions, allowing for a lower ON voltage and improved short-circuit capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ratio of dummy trenches (stabilizing plate) is increased to suppress oscillation during short-circuiting, then short-circuit capability is improved, but ON voltage and ON-state power dissipation increase
Solution Approach 1:
An insulating layer is introduced as an intermediary between the emitter electrode and the stabilizing plate. This mediator allows the stabilizing plate to suppress oscillation during short-circuiting while preventing excessive current flow that would increase ON voltage and power dissipation. The insulating layer enables the stabilizing plate to function primarily for electrical stabilization rather than current conduction.
Solution Approach 2:
The stabilizing plate is designed as a non-functional copy of the gate structure that mimics the trench geometry but does not conduct current during normal operation. By creating this copies structure with insulating material, the device gains the electrical stabilization benefits of increased trench ratio without the penalty of increased power dissipation that would result from actual current flow through additional conductive paths.
2Reliability
If the ratio of dummy trenches (stabilizing plate) is increased to suppress oscillation during short-circuiting, then short-circuit capability is improved, but ON-state power dissipation increases
Solution Approach 1:
The insulating layer acts as a mediator that decouples the stabilizing plate from the current conduction path during ON state. This allows the stabilizing plate to perform its oscillation suppression function while the insulating layer prevents additional current flow that would generate excess power dissipation, thereby reducing energy loss during normal operation.
Solution Approach 2:
The current conduction function is extracted from the stabilizing plate by introducing the insulating layer. This separation allows the stabilizing plate to专注于 its primary function of suppressing oscillation during short-circuiting, while the insulating layer ensures that current flows only through the intended conductive paths, minimizing unnecessary energy loss.
3Loss of energy
If trench gate type IGBT structure is adopted to decrease loss, then gate capacitance is increased, but oscillation occurs during short-circuiting
Solution Approach 1:
The stabilizing plate connected through the insulating layer provides a feedback mechanism that counteracts oscillations in gate voltage and current during short-circuiting. The insulating layer ensures that this feedback is electrical in nature rather than involving significant current flow, allowing the system to dampen oscillations while maintaining low loss characteristics.
Solution Approach 2:
The electrical parameters of the stabilizing plate region are changed by introducing the insulating layer, which modifies the capacitance and impedance characteristics. This parameter change allows the stabilizing plate to provide oscillation suppression feedback while the insulating layer prevents excessive current flow that would increase power loss, thus maintaining low loss operation.
Data Source
AI summary
A stabilizing plate portion is formed in a region of a first main surface lying between first and second insulated gate field effect transistor portions. The stabilizing plate portion includes a first stabilizing plate arranged closest to the first insulated gate field effect transistor portion and a second stabilizing plate arranged closest to the second insulated gate field effect transistor portion. An emitter electrode is electrically connected to an emitter region of each of the first and second insulated gate field effect transistor portions, electrically connected to each of the first and second stabilizing plates, and arranged on the entire first main surface lying between the first and second stabilizing plates, with an insulating layer being interposed.