Oxide Thin Film Transistor Activation via Magnetic Field

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Solution Overview

Problem

The challenge is to fabricate high-performance oxide thin film transistors using oxide semiconductor layers on flexible substrates without damaging them due to high temperatures, which degrades the transistor performance and requires additional protective measures, increasing costs.

Innovation Solution

The solution involves forming an oxide semiconductor layer using a magnetic field under a low-temperature environment, with heat treatment at less than 300°C and a rotating magnetic field applied to the substrate, which generates Joule heat for activation, allowing chemical bonding without damaging flexible substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high temperature heat treatment is applied to activate the oxide semiconductor layer, then the electrical characteristics of the transistor are improved, but the flexible substrate is damaged

Engineering Contradiction:
Improveelectrical characteristicsVSAvoidsubstrate damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the temperature parameter from conventional high temperature (above 300°C) to low temperature (below 300°C, specifically 100-250°C) for heat treatment. This parameter change allows activation of the oxide semiconductor layer while preventing damage to the flexible substrate, resolving the contradiction between improving electrical characteristics and avoiding substrate damage

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a magnetic field as an intermediary mechanism to enhance the heat treatment process. By applying a magnetic field (1-10 mT strength) during low-temperature heat treatment, the oxide semiconductor layer is activated more effectively at lower temperatures, eliminating the need for high-temperature processing that would damage the flexible substrate

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If conventional high temperature processing is used, then the oxide semiconductor layer is properly activated, but additional protective measures and equipment are required, increasing cost

Engineering Contradiction:
Improvetransistor performanceVSAvoidfabrication process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the temperature parameter to low temperature (below 300°C) and introduces magnetic field application as an additional control parameter. This allows proper activation of the oxide semiconductor layer using simpler, lower-cost equipment without requiring complex high-temperature processing systems or additional protective measures

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the conventional thermal activation mechanism (relying solely on high temperature) with a combined magnetic field and low-temperature heat treatment mechanism. This substitution enables effective semiconductor layer activation using less complex equipment and processes

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 method enables the fabrication of high-performance oxide thin film transistors at a lower cost and with reduced substrate damage, using a simple process, while maintaining the integrity of flexible substrates and improving electrical characteristics.

Implementation Method 1

the activation proceeds by activation energy provided by Joule heat generated from eddy current occurring in the oxide semiconductor layer by a change in the magnetic flux

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Implementation Method 2

Joule heat generated from eddy current occurring in the oxide semiconductor layer by a change in the magnetic flux

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

the activation proceeds by activation energy provided by Joule heat generated from eddy current occurring in the oxide semiconductor layer by a change in the magnetic flux

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS10008589B2Oxide thin film transistor and method of fabricating the same
Publication Date: 2018.06.26 IND ACADEMIC COOP FOUND YONSEI UNIV

AI summary

Disclosed are an oxide thin film transistor and a method of fabricating the same. The oxide thin film transistor according to an embodiment of the present disclosure includes a gate electrode formed on a substrate, a gate insulating layer formed on the gate electrode, an oxide semiconductor layer as a semiconductor active layer, and source and drain electrodes formed on the oxide semiconductor layer. The oxide semiconductor layer is activated by heat of less than 300° C. and a change in the magnetic flux of an applied magnetic field. More specifically, the activation proceeds by activation energy provided by Joule heat generated from eddy current occurring in the oxide semiconductor layer by a change in the magnetic flux, and the heat of less than 300° C.