Oxide Semiconductor Transistor Insulator Stack for Low Leakage

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Solution Overview

Problem

Existing semiconductor devices face challenges in achieving favorable electrical characteristics, reliability, high on-state current, small variation in transistor characteristics, miniaturization, high integration, and low power consumption, while maintaining favorable productivity.

Innovation Solution

A semiconductor device structure is designed with a specific configuration of insulators and electrodes, including a gate electrode, gate insulating film, source and drain electrodes, and insulators with opening portions, utilizing aluminum oxide and silicon nitride insulators, and a manufacturing method involving dry etching and deposition of oxide semiconductor layers to form island shapes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If transistor size is reduced to increase integration density, then device miniaturization and high integration are achieved, but manufacturing precision and electrical characteristics deteriorate

Engineering Contradiction:

Improveintegration densityVSAvoidtransistor characteristic variation

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the material parameter from conventional semiconductor to oxide semiconductor, which fundamentally alters the electrical characteristics and enables high integration with maintained precision through the material's inherent stability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures including oxide semiconductor layers combined with specific insulator materials (aluminum oxide, silicon nitride) to achieve both miniaturization and stable electrical characteristics

Inventive Principle:

Principle #40Composite materials

2Loss of energy

If oxide semiconductor transistor is used to reduce leakage current, then power consumption is reduced, but manufacturing complexity increases

Engineering Contradiction:

Improveleakage currentVSAvoidinsulator layer structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent segments the insulator structure into multiple functional layers (first insulator aluminum oxide, second insulator silicon nitride, third insulator aluminum oxide) where each layer performs a specific function in controlling leakage and enabling low power operation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different material properties to different regions - aluminum oxide for oxygen supply and silicon nitride for barrier properties - creating local quality variations that reduce leakage current while managing device complexity

Inventive Principle:

Principle #3Local quality

3Reliability

If aluminum oxide insulator is used to supply oxygen, then electrical characteristics are improved, but device complexity increases

Engineering Contradiction:

Improveelectrical characteristicsVSAvoidmulti-layer insulator structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The aluminum oxide insulator layers serve multiple functions simultaneously: oxygen supply to the oxide semiconductor, electrical insulation, and structural support, thereby improving reliability without proportionally increasing complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

The solution provides a semiconductor device with favorable electrical characteristics, reliability, high on-state current, small transistor characteristic variation, miniaturization, high integration, and low power consumption, while ensuring favorable productivity.

Implementation Method 1

heat treatment is performed in a nitrogen atmosphere or an oxygen atmosphere, oxygen is supplied from the second insulator to the oxide semiconductor layer

Methodology Applied

Scientific EffectOxygen diffusion: Diffusion

Implementation Method 2

the third insulator is in contact with the side surface of the second insulator and the top surface of the first insulator

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 3

a manufacturing method involving dry etching and deposition of oxide semiconductor layers

Methodology Applied

Scientific EffectPlasma etching: Plasma

Data Source

PatentUS12439581B2Semiconductor device and method for manufacturing semiconductor device

Publication Date: 2025.10.07 SEMICON ENERGY LAB CO LTD

AI summary

A semiconductor device having favorable electrical characteristics is provided. The semiconductor device includes a transistor including a gate electrode, a source electrode, and a drain electrode; a first insulator over the transistor; a second insulator over the first insulator; a third insulator over the second insulator; a first electrode in contact with the top surface of the source electrode; and a second electrode in contact with the top surface of the drain electrode. The second insulator includes a first opening portion overlapping with the source electrode and a second opening portion overlapping with the drain electrode. The third insulator is in contact with the side surface of the second insulator and the top surface of the first insulator inside the first opening portion and the second opening portion. The first electrode is positioned through the first opening portion. The second electrode is positioned through the second opening portion.