Crystalline Oxide Semiconductor Structure for Low-Resistance Source/Drain

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Solution Overview

Problem

Existing semiconductor technologies face challenges in achieving high carrier mobility and uniform device characteristics, as amorphous silicon lacks mobility while polysilicon requires recrystallization and may not ensure uniformity.

Innovation Solution

A semiconductor device is fabricated with a crystalline first oxide semiconductor pattern on a substrate, a gate pattern, and a crystalline second oxide semiconductor pattern on both sides of the gate pattern, increasing the thickness of the source/drain region through a crystallization process of an amorphous oxide semiconductor material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the thickness of the source/drain region is increased to reduce contact resistance, then the contact resistance decreases, but the thickness of the channel region may increase which affects device characteristics

Engineering Contradiction:

Improvecontact resistanceVSAvoidchannel region thickness uniformity

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies local quality by forming a thicker source/drain region only in specific areas where contact resistance needs reduction, while maintaining the original channel region thickness. The crystalline oxide semiconductor layer is selectively formed in the source/drain regions through a crystallization process that does not affect the channel region, achieving local thickness enhancement without compromising channel uniformity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the oxide semiconductor layer into different regions with different thicknesses: the channel region maintains its original thickness while the source/drain regions are enhanced with an additional crystalline layer. This segmentation allows independent optimization of each region's properties.

Inventive Principle:

Principle #1Segmentation

2Reliability

If polysilicon is used to achieve high carrier mobility, then carrier mobility increases, but a recrystallization process is required and uniform device characteristics cannot be secured

Engineering Contradiction:

Improvecarrier mobilityVSAvoiddevice characteristics uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the material parameter from polysilicon to crystalline oxide semiconductor, which inherently provides high carrier mobility without requiring recrystallization processes. The crystalline oxide semiconductor layer is formed through controlled crystallization at lower temperatures, achieving both high mobility and uniformity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses crystalline oxide semiconductor as a composite material that combines the advantages of both amorphous and crystalline materials: the ease of formation like amorphous materials and the high carrier mobility like crystalline materials, without the drawbacks of each.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If amorphous silicon is used to secure uniform device characteristics through simple process, then manufacturing simplicity is achieved, but carrier mobility remains low

Engineering Contradiction:

Improveprocess simplicityVSAvoidcarrier mobility

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent utilizes phase transition by forming a crystalline oxide semiconductor layer from an amorphous state through controlled crystallization. This phase transition enables the material to achieve high carrier mobility characteristic of crystalline materials while maintaining the process simplicity of amorphous material deposition.

Inventive Principle:

Principle #36Phase transitions

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 reduces contact resistance in the source/drain region by increasing the thickness of the source/drain region, maintaining channel region thickness, and ensuring high carrier mobility and uniform device characteristics.

Implementation Method 1

performing a crystallization process to transform a part of the amorphous oxide semiconductor material in contact with the first oxide semiconductor pattern into a crystalline second oxide semiconductor pattern

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Data Source

PatentUS20250254927A1Semiconductor device including crystalline oxide semiconductor and method for fabricating the same

Publication Date: 2025.08.07 SK HYNIX INC

AI summary

A semiconductor device may include a substrate; a crystalline first oxide semiconductor pattern disposed on the substrate; a gate pattern disposed on the first oxide semiconductor pattern; and a crystalline second oxide semiconductor pattern disposed on the first oxide semiconductor pattern on both sides of the gate pattern. A method for fabricating a semiconductor device may include forming a crystalline first oxide semiconductor pattern on a substrate; forming a gate pattern disposed on the first oxide semiconductor pattern; forming an amorphous oxide semiconductor material on the first oxide semiconductor pattern on both sides of the gate pattern; and performing a crystallization process to transform a part of the amorphous oxide semiconductor material in contact with the first oxide semiconductor pattern into a crystalline second oxide semiconductor pattern.