FeFET Semiconductor Structure With Low-Temperature SUT Crystallization

Solution Overview

Problem

Ferroelectric field-effect transistors (FeFETs) face challenges due to weak crystallization and oxygen-related defects in the ferroelectric and metal oxide semiconductor materials, which impact electrical characteristics and stability, and existing thermal treatments can damage BEOL interconnect structures.

Innovation Solution

A simultaneous ultraviolet and thermal (SUT) treatment is applied to the ferroelectric and metal oxide semiconductor materials to improve their film qualities, reducing oxygen vacancies and enhancing bonding without exceeding the thermal budget of the BEOL process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermal treatment is applied to improve crystalline quality and reduce oxygen vacancies in ferroelectric and metal oxide semiconductor materials, then the electrical characteristics and stability are improved, but the BEOL interconnect structures are damaged

Engineering Contradiction:

Improveelectrical characteristics and stabilityVSAvoiddamage to BEOL interconnect structures

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies simultaneous ultraviolet and thermal (SUT) treatment to modify the physical and chemical parameters of the ferroelectric and metal oxide semiconductor materials. This combined treatment approach changes the crystalline structure and reduces oxygen vacancies without requiring excessive thermal energy that would damage BEOL interconnects, thus resolving the contradiction between improving electrical characteristics and protecting sensitive interconnect structures

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The SUT treatment acts as an intermediary process that mediates between the need for high-quality material crystallization and the constraint of low thermal budget. The ultraviolet component provides photochemical assistance that reduces the thermal load required for crystallization, enabling improved material quality while protecting temperature-sensitive BEOL interconnect structures from thermal damage

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If high temperature thermal treatment is used to enhance crystalline quality, then oxygen vacancies are reduced and bonding is enhanced, but the thermal budget of the BEOL process is exceeded

Engineering Contradiction:

Improvecrystalline qualityVSAvoidthermal budget

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

The patent merges ultraviolet irradiation with thermal treatment in a simultaneous SUT process. This combination allows the ultraviolet energy to contribute to the crystallization process, reducing the burden on thermal energy and enabling high-quality crystalline formation at lower temperatures that fit within the BEOL thermal budget constraints

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent partially replaces the purely thermal mechanism with a photochemical mechanism by introducing ultraviolet irradiation. This substitution reduces the reliance on high thermal energy for crystallization, allowing crystalline quality improvement without exceeding the thermal budget limitations of the BEOL process

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

The SUT treatment enhances the crystalline quality and stability of the ferroelectric and metal oxide semiconductor layers at a lower temperature, improving the electrical characteristics of FeFETs while being compatible with BEOL interconnect fabrication.

Implementation Method 1

A simultaneous ultraviolet and thermal (SUT) treatment is applied to the ferroelectric and metal oxide semiconductor materials to improve their film qualities, reducing oxygen vacancies and enhancing bonding without exceeding the thermal budget of the BEOL process

Methodology Applied

Scientific EffectUltraviolet treatment: Photo-oxidation

Implementation Method 2

A simultaneous ultraviolet and thermal (SUT) treatment is applied to the ferroelectric and metal oxide semiconductor materials to improve their film qualities, reducing oxygen vacancies and enhancing bonding without exceeding the thermal budget of the BEOL process

Methodology Applied

Scientific EffectThermal treatment: Annealing

Data Source

PatentUS20240389343A1Semiconductor structure and method of forming the same

Publication Date: 2024.11.21 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method for forming a semiconductor structure includes following operations. A substrate is received. The substrate includes a first dielectric layer and a conducive layer formed in the first dielectric layer. A ferroelectric layer is formed over the first dielectric layer and the conductive layer. A metal oxide semiconductor layer is formed over the ferroelectric layer. An SUT treatment is performed. A temperature of the SUT treatment is less than approximately 400° C.