Semiconductor Device Gate Electrode Segmentation

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Solution Overview

Problem

In semiconductor devices, there is a contradiction between maintaining performance and reducing the gate-input charge amount, as a smaller opposing area between the gate electrode and the semiconductor substrate is necessary for fast switching but can lead to performance deterioration.

Innovation Solution

The semiconductor device features a trench structure with intermittently appearing carrier-injected regions and a continuously present drift region, where the gate electrode's end surface opposing the body region is displaced to the rear surface side, reducing the opposing area and gate-input charge amount without compromising performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the opposing area between the gate electrode and the semiconductor substrate is decreased to reduce the gate-input charge amount, then the switching speed is improved, but the semiconductor device performance deteriorates

Engineering Contradiction:

Improveswitching speedVSAvoidsemiconductor device performance

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The gate electrode is divided into multiple sections along the trench length, with each section having different opposing areas. The first gate electrode section has a larger opposing area for reliable inversion layer generation, while the second gate electrode section has a smaller opposing area to reduce overall gate-input charge. This segmentation allows different portions of the gate electrode to serve different functions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the gate electrode are designed with different opposing areas to the semiconductor substrate. The first section maintains sufficient opposing area for effective inversion layer generation and device performance, while the second section reduces opposing area to minimize gate-input charge. This local differentiation optimizes both switching speed and performance.

Inventive Principle:

Principle #3Local quality

2Reliability

If the opposing area of the gate electrode is increased to maintain inversion layer generation, then the semiconductor device performance is maintained, but the gate-input charge amount increases

Engineering Contradiction:

Improveinversion layer generationVSAvoidgate-input charge amount

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The gate electrode is segmented into a first section with sufficient opposing area for inversion layer generation and a second section with reduced opposing area. This allows the device to maintain the minimum necessary opposing area for reliable operation while reducing the total opposing area to minimize gate-input charge requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of providing sufficient opposing area across the entire gate electrode length, the invention provides sufficient opposing area only in the first section where it is most needed for inversion layer generation. The second section has partial opposing area reduction, achieving adequate performance with reduced overall gate-input charge.

Inventive Principle:

Principle #16Partial or excessive action

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 configuration allows for reduced gate-input charge requirements while maintaining semiconductor device performance by optimizing the opposing area and inversion layer generation, thereby enhancing switching speed and efficiency.

Implementation Method 1

A phenomenon in which a voltage is applied to a gate electrode and an inversion layer is generated at a position opposing the gate electrode via a gate insulating film corresponds to a phenomenon of storing charges in one electrode of a capacitor and causing a dielectric phenomenon in the other electrode of the capacitor.

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

Methodology Applied

Scientific EffectDielectric phenomenon: Dielectric

Data Source

PatentUS10002951B2Semiconductor device

Publication Date: 2018.06.19 DENSO CORP

AI summary

A semiconductor device may include a trench, a gate insulating film covering the trench, first conductive type carrier-injected regions intermittently appearing along a predetermined direction, a first conductive type drift region continuously present along the predetermined direction, a second conductive type body region filling a gap between the carrier-injected regions as seen along the predetermined direction, and a gate electrode disposed in the trench. A front end surface located on the front surface side of the gate electrode may include a first end surface at a portion of the gate electrode opposing the carrier-injected regions via the gate insulating film, and a second end surface at least a part of a portion of the gate electrode opposing the body region in the gap. The second end surface may be displaced to the rear surface side relative to the first end surface.