Remote Gate Contact Regions for Trench Semiconductor Devices

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Solution Overview

Problem

Conventional semiconductor devices face challenges with excess cost, decreased reliability, and low performance due to inadequate conductivity modulation, particularly in high-voltage structures, which results in longer recovery times and snappy reverse characteristics.

Innovation Solution

The semiconductor device incorporates remote gate contact regions within trench gate structures to control minority carrier injection, improving switching characteristics, and optional lifetime control techniques like electron beam irradiation or platinum doping can be used for higher voltage devices to achieve optimal tradeoffs between forward voltage and stored charge recovery time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional semiconductor devices are used without remote gate contact regions, then manufacturing is simpler, but conductivity modulation is inadequate resulting in low performance and longer recovery times

Engineering Contradiction:

Improveconductivity modulation performanceVSAvoidtrench gate structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The gate structure is segmented into two distinct parts: a trench gate structure extending into the semiconductor layer and a separate remote gate contact region disposed in the mesa region. This segmentation allows independent optimization of each component's function, with the trench gate providing primary control and the remote contact region enhancing conductivity modulation without interfering with the trench gate operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The remote gate contact region acts as an intermediary element that mediates between the control signal and the semiconductor layer. By positioning this contact region in the mesa area rather than directly in the trench, it provides indirect control that enhances conductivity modulation while avoiding the complexities of direct trench contact, thus improving performance without proportionally increasing structural complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If lifetime control techniques like electron beam irradiation or platinum doping are used, then switching performance improves, but manufacturing cost increases and contamination risks arise

Engineering Contradiction:

Improveswitching performanceVSAvoidcontamination risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the lifetime control function from traditional methods (electron beam irradiation and platinum doping) and implements it through a structural modification - the remote gate contact region. This removes the need for harmful contamination processes while achieving the same switching performance improvement through controlled carrier injection from the remote contact.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using expensive and potentially contaminating materials like platinum or complex electron beam irradiation equipment, the invention employs a simpler, more cost-effective approach using standard semiconductor fabrication processes to create the remote gate contact region. This provides the necessary switching performance without the high costs and contamination risks of alternative methods.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 approach enhances switching performance while reducing manufacturing costs and potential contamination risks, providing improved reliability and efficiency in conductivity modulation.

Implementation Method 1

The remote gate contact regions are configured to control the amount of minor carrier injection thereby improving switching characteristics

Methodology Applied

Scientific EffectMinority carrier injection:

Implementation Method 2

optional lifetime control techniques like electron beam irradiation or platinum doping can be used for higher voltage devices

Methodology Applied

Scientific EffectElectron beam irradiation: Electron Beam

Data Source

PatentUS11469312B2Remote contacts for a trench semiconductor device and methods of manufacturing semiconductor devices

Publication Date: 2022.10.11 SEMICON COMPONENTS IND LLC

AI summary

A semiconductor device structure comprises a region of semiconductor material comprising a first conductivity type, a first major surface, and a second major surface opposite to the first major surface. A first trench gate structure includes a first trench extending from the first major surface into the region of semiconductor material, a first dielectric structure is over sidewall surfaces and a portion of a lower surface of the first trench, wherein the first dielectric structure comprises a first opening adjacent to the lower surface of the first trench, a first recessed contact extends through the first opening, and a first contact region is over the first recessed contact within the first trench, wherein the first recessed contact and the first contact region comprise different materials. A first doped region comprising a second dopant conductivity type opposite to the first conductivity type is in the region of semiconductor material and is spaced apart from the first major surface and below the first trench. A gate contact region is in the region of semiconductor material and is electrically connected to the first doped region.