Split-Shielded Trench Gate IGBT for Low Switching Loss
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Solution Overview
Problem
Conventional IGBT devices face trade-offs between conduction loss, turn-off switching losses, short circuit ruggedness, and breakdown voltage, limiting their performance and efficiency in high-power applications.
Innovation Solution
A trench IGBT device with a shielded gate and optional dummy trench is developed, featuring a two-dimensional channel with a lateral and vertical component, which reduces switching losses and increases breakdown voltage, while allowing for a smaller cell pitch and improved short circuit ruggedness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a heavily doped N layer is added below the channel region to enhance carrier injection, then conductivity improves, but breakdown voltage decreases and Crss capacitance worsens
Solution Approach 1:
The gate structure is divided into two separate gate electrodes with an insulation layer between them, allowing independent control of carrier injection into different regions. This enables enhancement of conductivity without adding a heavily doped layer that would compromise breakdown voltage
Solution Approach 2:
A gate insulation layer is introduced as an intermediary between the two gate electrodes and the semiconductor regions. This insulation layer enables controlled carrier injection through the gate structure without requiring heavily doped regions, thereby maintaining breakdown voltage while improving conductivity
2Power
If cell pitch is reduced to increase current density, then power density improves, but short circuit ruggedness decreases due to higher saturation current
Solution Approach 1:
The segmented gate structure with two electrodes and an insulation layer enables better control of current distribution and saturation current density. This allows reduced cell pitch for higher power density while maintaining short circuit ruggedness through improved current control mechanisms
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 achieves lower turn-on and turn-off losses, reduced capacitance, and enhanced breakdown voltage, improving the overall efficiency and ruggedness of the IGBT device.
Implementation Method 1
a gate insulation layer between the first gate electrode and the second gate electrode
Implementation Method 2
the first gate electrode is configured to control injection of carriers into a channel region
Implementation Method 3
the second gate electrode is configured to control injection of carriers into a drift region... the lightly doped drift region undergoes high level carrier injection from the bottom P collector region resulting in its conductivity modulation
Implementation Method 4
the lightly doped drift region undergoes high level carrier injection from the bottom P collector region
Data Source
AI summary
This invention discloses an insulated gate bipolar transistor (IGBT) device formed in a semiconductor substrate. The IGBT device has a split-shielded trench gate that includes an upper gate segment and a lower shield segment. The IGBT device may further include a dummy trench filled with a dielectric layer disposed at a distance away from the split-shielded trench gate. The IGBT device further includes a body region extended between the split-shielded trench gate and the dummy trench encompassing a source region surrounding the split-shielded trench gate near a top surface of the semiconductor substrate. The IGBT device further includes a heavily doped N region disposed below the body region and above a source-dopant drift region above a bottom body-dopant collector region at a bottom surface of the semiconductor substrate. In an alternative embodiment, the IGBT may include a planar gate with a trench shield electrode.