Double Transition Metal Dichalcogenide FET Channels

Solution Overview

Problem

Field effect transistors (FETs) using transition metal dichalcogenides as channels face challenges in achieving a desirable on/off ratio and high carrier mobility, with existing materials either having low carrier mobility or undesirable on/off characteristics.

Innovation Solution

The design of FETs with double transition metal dichalcogenide channels, where the first and second channels are stacked on a substrate, with source and drain electrodes contacting both, and a gate electrode controlling the channels, along with an insulating interlayer and passivation layer to enhance carrier mobility by reducing contact resistance and increasing current flow paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If transition metal dichalcogenide is used as channel material, then on/off ratio characteristic is improved, but carrier mobility deteriorates

Engineering Contradiction:

Improveon/off ratioVSAvoidcarrier mobility

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The channel is divided into multiple segments (first channel layer and second channel layer) stacked vertically. Each layer contacts the source and drain electrodes, creating multiple parallel conduction paths. This segmentation allows the device to maintain the desirable on/off ratio of transition metal dichalcogenide while improving carrier mobility through increased current flow paths.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single two-dimensional channel layer to a vertically stacked multi-layer structure. By adding the vertical dimension with multiple channel layers, the device increases the effective conduction area and current flow paths without compromising the material's intrinsic on/off ratio characteristics. This dimensional expansion resolves the contradiction between on/off ratio and carrier mobility.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Device complexity

If single channel structure is used, then device simplicity is maintained, but carrier mobility is limited

Engineering Contradiction:

Improvechannel structureVSAvoidcarrier mobility

Core Design Contradiction:

Device complexityVSSpeed

Solution Approach 1:

The channel is divided into multiple segments (first channel layer and second channel layer) stacked vertically. Each layer contacts the source and drain electrodes, creating multiple parallel conduction paths. This segmentation allows the device to maintain the desirable on/off ratio of transition metal dichalcogenide while improving carrier mobility through increased current flow paths.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The channel structure employs a nested configuration where the first channel layer and second channel layer are stacked one on top of the other, with source and drain electrodes penetrating through both layers. This nested arrangement increases the effective conduction area and carrier mobility while maintaining a compact vertical structure that does not significantly increase device footprint.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS8916914B2Field effect transistor having double transition metal dichalcogenide channels

Publication Date: 2014.12.23 SAMSUNG ELECTRONICS CO LTD

AI summary

A field effect transistor (FET) includes first and second channels stacked on a substrate, the first and second channels formed of a transition metal dichalcogenide, a source electrode and a drain electrode contacting both the first channel and the second channel, each of the source electrode and the drain electrode having one end between the first channel and the second channel, and a first gate electrode corresponding to at least one of the first channel and the second channel.