HfO2 Ferroelectric FeFET Integration in CMOS Front-End

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Solution Overview

Problem

Implementing ferroelectric artificial synaptic devices in the CMOS front-end is challenging due to incompatibilities with perovskite ferroelectrics, such as thermal stability issues and contamination risks, which hinder the integration of synaptic elements in deep learning networks.

Innovation Solution

The use of hafnium oxide (HfO2)-based ferroelectric layers in field-effect transistors (FETs) that are compatible with CMOS front-end processing, allowing for the co-fabrication of ferroelectric FETs and logic FETs, leveraging thermal stability and compatibility with high thermal budgets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If perovskite ferroelectrics are used in CMOS back-end, then ferroelectric artificial synaptic devices can be implemented, but thermal stability issues and contamination risks arise due to incompatibility with CMOS front-end processing

Engineering Contradiction:

Improvecompatibility with CMOS processingVSAvoidthermal stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the material parameter from perovskite ferroelectric to HfO2-based ferroelectric, which has a higher Curie temperature and maintains ferroelectric properties at CMOS front-end processing temperatures. This parameter change resolves the thermal stability issue while enabling CMOS compatibility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses HfO2-based ferroelectric material as a composite solution that combines the desired ferroelectric properties with thermal stability compatible with CMOS processing. This composite material approach allows integration of synaptic devices in the CMOS front-end without the contamination and stability issues of perovskite materials

Inventive Principle:

Principle #40Composite materials

2Reliability

If perovskite ferroelectrics are used, then synaptic weight storage is achieved, but contamination risks and process incompatibility hinder integration

Engineering Contradiction:

Improvesynaptic weight storageVSAvoidintegration with CMOS front-end

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the material composition from lead-containing perovskite to HfO2-based ferroelectric, eliminating contamination risks while maintaining synaptic weight storage capability. This parameter change enables ease of manufacture through standard CMOS front-end processes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent adopts HfO2-based ferroelectric material that can be processed using standard CMOS front-end techniques, replacing the need for specialized perovskite processing. This approach simplifies manufacturing by using readily available, well-established CMOS processes

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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

Enables the successful integration of ferroelectric artificial synaptic devices in the CMOS front-end, ensuring thermal stability and compatibility with existing CMOS processing, thereby facilitating the implementation of synaptic elements in deep learning networks.

Implementation Method 1

forming at least one ferroelectric FET (FeFET) on the substrate in the first active area having a ferroelectric material including a hafnium oxide (HfO2)-based material

Methodology Applied

Scientific EffectFerroelectricity:

Implementation Method 2

the at least one logic FET has a gate dielectric including the HfO2-based material

Methodology Applied

Scientific EffectDielectric properties: Dielectric

Data Source

PatentUS10686039B2Artificial synapse with hafnium oxide-based ferroelectric layer in CMOS front-end

Publication Date: 2020.06.16 SAMSUNG ELECTRONICS CO LTD

AI summary

Artificial synaptic devices with a HfO2-based ferroelectric layer that can be implemented in the CMOS front-end are provided. In one aspect, a method of forming a FET device is provided. The method includes: forming a shallow STI region in a substrate separating a first active area of the substrate from a second active area of the substrate; forming at least one FeFET on the substrate in the first active area having a ferroelectric material including a HfO2-based material; and forming at least one logic FET alongside the at least one FeFET on the substrate in the second active area, wherein the at least one logic FET has a gate dielectric including the HfO2-based material. A FET device formed by the present techniques is also provided.