Oxygen Capturing Film Gate Structure Work Function Stability

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Solution Overview

Problem

As semiconductor devices become miniaturized, variations in the gate electrode structure can significantly affect their performance, particularly due to changes in the work function caused by impurities, leading to unreliable operation of transistors.

Innovation Solution

A semiconductor device is designed with a gate structure that includes a gate insulating film, a work function adjusting film, a separation film, an oxygen capturing film, and a gap-fill film, where the oxygen capturing film is spaced apart from the gate insulating film to prevent oxygen introduction and maintain the work function, thereby ensuring reliable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the gate structure is miniaturized to improve device density and performance, then productivity and device capability are improved, but the gate electrode structure becomes more sensitive to impurities and manufacturing variations, causing work function changes and reduced reliability

Engineering Contradiction:

Improvedevice densityVSAvoidwork function stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

An oxygen capturing film is introduced as an intermediary layer between the work function adjusting film and the external environment. This film selectively captures oxygen impurities that may enter the gate structure, thereby protecting the work function adjusting film from oxidation and maintaining stable electrical characteristics in miniaturized devices

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The oxygen capturing film is positioned and configured in advance to preemptively capture oxygen impurities before they can reach and alter the work function adjusting film. This preliminary protective action prevents work function drift that would otherwise occur during device operation

Inventive Principle:

Principle #10Preliminary action

2Length of moving object

If the gate structure dimensions are reduced to achieve further miniaturization, then device scaling is improved, but the impact of small variations in gate electrode structure on transistor operation becomes more significant, reducing reliability

Engineering Contradiction:

Improvegate structure dimensionVSAvoidtransistor operation reliability

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The oxygen capturing film serves as a protective intermediary that isolates the critical work function adjusting film from environmental oxygen. This mediation ensures that even in highly miniaturized structures where manufacturing variations are magnified, the gate electrode's electrical properties remain stable and predictable

Inventive Principle:

Principle #24Intermediary (Mediator)

3Quantity of substance

If oxygen is introduced into the gate structure during manufacturing or operation, then the work function of the gate electrode changes, but this leads to unreliable transistor operation

Engineering Contradiction:

Improveoxygen concentrationVSAvoidtransistor operation reliability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The oxygen capturing film converts the potentially harmful presence of oxygen into a beneficial effect by selectively binding oxygen impurities away from the work function adjusting film. This transforms oxygen, which would otherwise degrade device reliability, into a captured species that is isolated and harmless to the gate electrode's electrical characteristics

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The oxygen capturing film acts as a mediator that interacts with oxygen impurities through chemical adsorption or bonding, preventing these impurities from reaching the work function adjusting film and causing unwanted changes in the gate electrode's electrical properties

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively prevents changes in the work function of the gate structure, maintaining reliable transistor operation by blocking oxygen ingress and maintaining the initially designed work function value, thus enhancing the performance and stability of semiconductor devices.

Implementation Method 1

an oxygen capturing film on the separation film and configured to capture oxygen introduced from the outside of the gate structure

Methodology Applied

Scientific EffectOxygen capture: Absorption (physical)

Data Source

PatentUS10109629B2Semiconductor devices including gate structures with oxygen capturing films

Publication Date: 2018.10.23 SAMSUNG ELECTRONICS CO LTD

AI summary

A semiconductor device includes: a semiconductor substrate including an active region and a gate structure on the active region. The gate structure includes a gate insulating film; a work function adjusting film on the first gate insulating film; a separation film on the work function adjusting film; and an oxygen capturing film on the separation film and configured to capture oxygen introduced from the outside of the first gate structure. The oxygen capturing film is spaced apart from a top surface of the first gate insulating film by about 70 Å to about 80 Å.