Oxide Semiconductor Transistors with Varying Electron Affinities

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Solution Overview

Problem

Current semiconductor technologies face challenges in achieving transistors with favorable electrical characteristics, high integration density, high productivity, and high-speed operation while maintaining low power consumption and long data retention.

Innovation Solution

The development of transistors with different electrical characteristics formed over the same layer using oxide semiconductor materials with varying electron affinities, where excess oxygen insulating layers are employed to enhance oxygen supply, and a multi-layered structure with overlapping electrodes and insulating layers is implemented to increase oxygen availability and improve channel formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If oxide semiconductor layers with different electron affinities are stacked to increase carrier mobility, then electrical characteristics are improved, but device complexity increases

Engineering Contradiction:

Improveelectrical characteristicsVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The semiconductor layer is segmented into multiple oxide semiconductor layers with different electron affinities (first oxide semiconductor layer with first electron affinity, second oxide semiconductor layer with second electron affinity). This segmentation allows each layer to contribute differently to carrier transport, improving overall electrical characteristics while maintaining manageable device structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the semiconductor structure are assigned different materials with specific electron affinities tailored to their functional requirements. The first oxide semiconductor layer and second oxide semiconductor layer have distinct electron affinities optimized for their respective positions in the device, enabling local optimization of electrical properties

Inventive Principle:

Principle #3Local quality

2Productivity

If transistor size is reduced to increase integration density, then productivity is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improveintegration densityVSAvoidmanufacturing precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Multiple functional layers are nested within a compact vertical structure, with the first oxide semiconductor layer, second oxide semiconductor layer, and insulating layers stacked together. This nesting approach achieves high integration density without requiring proportional reduction in feature sizes, thereby managing manufacturing precision requirements

Inventive Principle:

Principle #7Nested doll (Nesting)

3Speed

If operating speed is increased for high-speed operation, then productivity is improved, but power consumption increases

Engineering Contradiction:

Improveoperating speedVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The electron affinity parameter is changed across different oxide semiconductor layers to optimize carrier mobility and device performance. By adjusting material composition and electron affinity values, the device achieves high-speed operation with reduced power consumption through improved carrier transport efficiency rather than increased driving voltage

Inventive Principle:

Principle #35Parameter changes

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 enables transistors with improved electrical characteristics, increased integration density, high-speed operation, and low power consumption, while maintaining long data retention and high design flexibility.

Implementation Method 1

an insulating layer containing excess oxygen is used as an insulating layer below the semiconductor layer. By increasing the thickness of the insulating layer, a large amount of oxygen can be supplied to the semiconductor layer

Methodology Applied

Scientific EffectOxygen diffusion: Diffusion

Data Source

PatentUS10096720B2Transistor, semiconductor device, and electronic device

Publication Date: 2018.10.09 SEMICON ENERGY LAB CO LTD

AI summary

To provide a semiconductor device with high design flexibility. A first transistor and a second transistor having different electrical characteristics from those of the first transistor are provided over the same layer without significantly increasing the number of manufacturing steps. A semiconductor layer where a channel of the first transistor is formed and a semiconductor layer where a channel of the second transistor is formed are formed using semiconductor materials having different electron affinities. When an oxide semiconductor is used for the semiconductor layer, an insulating layer containing excess oxygen is used as an insulating layer below the semiconductor layer. By increasing the thickness of the insulating layer, a large amount of oxygen can be supplied to the semiconductor layer.