Trench Gate Semiconductor Layout for Avalanche Protection
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Solution Overview
Problem
Existing semiconductor devices face challenges in maintaining static and dynamic behavior, particularly in high-power applications, where avalanches can damage the gate insulation layer during switching events, leading to reduced performance and stability.
Innovation Solution
The semiconductor device incorporates a unique structure with a gate insulated transistor design featuring a semiconductor body with a drift region, multiple base regions, and trenches, including a first-type trench filled with conductive material and a second-type trench without the gate electrode, along with an electrically conductive layer above the third base region for capacitive coupling, which helps protect the gate insulation layer and manage charge carriers effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gate electrode is placed in every trench to improve device performance, then the transistor switching capability is improved, but the gate insulation layer becomes vulnerable to avalanche damage during switching events
Solution Approach 1:
The patent divides the trench structure into two types: first-type trenches containing gate electrodes for active transistor regions, and second-type trenches without gate electrodes for protective regions. This segmentation allows different functional zones within the same semiconductor device, enabling high-performance switching areas while protecting vulnerable gate insulation layers in other areas from avalanche damage during switching events.
Solution Approach 2:
The patent applies different structural configurations to different spatial locations within the semiconductor device. Specifically, gate electrodes are selectively placed in first-type trenches at certain locations while second-type trenches without gate electrodes are positioned at other locations. This local differentiation optimizes both device performance and reliability by matching the structural characteristics to the functional requirements of each region.
2Power
If the semiconductor device is designed to handle high currents and voltages, then the power processing capability is improved, but the risk of avalanche damage to the gate insulation layer increases
Solution Approach 1:
The patent introduces second-type trenches without gate electrodes as intermediary protective structures between the high-power active regions and the gate insulation layer. These second-type trenches act as mediators that redirect or absorb avalanche energy, preventing direct damage to the gate insulation layer while allowing the device to continue handling high currents and voltages in the active first-type trench regions.
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 design enhances the semiconductor device's ability to handle high currents and voltages while reducing the risk of avalanche damage to the gate insulation layer, improving both static and dynamic performance and extending the device's operational lifespan.
Implementation Method 1
The gate electrode extends into the first-type trench where it is separated from the semiconductor body by a gate insulation layer
Implementation Method 2
along with an electrically conductive layer above the third base region for capacitive coupling
Implementation Method 3
The arrangement with the second-type trench, the second base region and the third base region helps, inter alia, to protect the first-type trench, particularly the gate insulation layer therein, for example from avalanches during switching events
Data Source
Figure 1~2
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Figure 5~6
AI summary
The semiconductor device (100) comprises a semiconductor body (10) with a top side (11) and a bottom side (19). A first main electrode (2) is arranged on the top side and a second main electrode (3) is arranged on the bottom side. The semiconductor device comprises a gate electrode (4) and at least two trenches, namely a first-type trench (51) and a second-type trench (52). The semiconductor body comprises a drift region (14) of a first conductivity type and at least three base regions (13a, 13b, 13c) each of a second conductivity type. The semiconductor body further comprises an injection region (12) of the first conductivity type. The first main electrode is in electrical contact with the injection region. The gate electrode extends into the first-type trench. The second-type trench is free of the gate electrode. An electrically conductive layer (8) is arranged on the top side above the third base region and is electrically connected to an electrode. The electrically conductive layer is located close to the third base region so that it capacitively couples thereto.