Semiconductor Gate Electrode Structure for Reduced Gate-Drain Capacitance
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Solution Overview
Problem
Existing semiconductor devices face challenges in improving electrical properties, particularly in reducing switching delay and switching loss associated with gate-drain capacitance.
Innovation Solution
The semiconductor device incorporates a gate electrode with a first electrode portion covering the channel inversion region and a second electrode portion led out onto the drift region, partially exposing it, which reduces the facing area with the drain-drift region, thereby decreasing gate-drain capacitance and improving electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate electrode completely covers the gate insulating film over the drift region, then the gate control is more complete, but the gate-drain capacitance increases causing larger switching delay and switching loss
Solution Approach 1:
The gate electrode is divided into two distinct portions: a first electrode portion that covers the gate insulating film over the channel inversion region, and a second electrode portion that is led out onto the gate insulating film over the drift region. This segmentation allows the gate electrode to maintain control over the channel while reducing the overlapping area with the drain region, thereby decreasing gate-drain capacitance and switching delay.
Solution Approach 2:
Different portions of the gate electrode have different functions: the first electrode portion provides gate control over the channel inversion region, while the second electrode portion extends onto the drift region to reduce capacitance. This local differentiation optimizes both control completeness and switching performance by assigning specific functions to specific regions of the gate electrode.
2Reliability
If the gate electrode completely covers the gate insulating film over the drift region, then the electrical stability is improved, but the switching loss increases due to higher gate-drain capacitance
Solution Approach 1:
The gate electrode is segmented into a first electrode portion for channel control and a second electrode portion that reduces drain overlap. This segmentation maintains electrical stability through the first portion while the second portion minimizes capacitive coupling with the drain, reducing switching loss.
Solution Approach 2:
The geometry of the gate electrode is changed by leading out the second electrode portion onto the gate insulating film, reducing the overlapping area with the drain region. This parameter change (reduced overlap area) directly decreases gate-drain capacitance, thereby reducing switching loss while maintaining adequate control through the first electrode portion.
Data Source
AI summary
A semiconductor device includes a chip, a drain region, a source region formed at the surface layer portion of the main surface at a distance from the drain region, a channel inversion region formed on a side of the source region between the drain region and the source region in the surface layer portion of the main surface, a drift region formed in a region between the drain region and the channel inversion region in the surface layer portion of the main surface, a gate insulating film having a first portion that covers the channel inversion region on the main surface and a second portion that covers the drift region on the main surface, and a gate electrode having a first electrode portion covering the first portion and a second electrode portion led out from the first electrode portion onto second portion so as to partially expose second portion.