FinFET Source/Drain Protection Layer for FinFET Reliability

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Solution Overview

Problem

The challenge in semiconductor manufacturing lies in forming reliable fin-like field effect transistors (FinFETs) as feature sizes decrease, making fabrication processes increasingly difficult due to the complexity of achieving precise control over fin structures and source/drain regions.

Innovation Solution

The process involves forming fin structures over a semiconductor substrate, growing epitaxial source/drain structures, and applying a semiconductor protection layer with a higher germanium concentration to protect these structures during subsequent processing steps, such as etching and cleaning, while also forming gate stacks and isolation features to enhance device performance and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If feature sizes continue to decrease to increase functional density, then production efficiency and cost are improved, but fabrication process difficulty and reliability increase

Engineering Contradiction:

Improveproduction efficiencyVSAvoidfabrication process difficulty

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

A semiconductor protection layer is formed over the fin structure and source/drain regions before subsequent etching and processing steps. This preliminary protective action prevents damage to critical structures during manufacturing, enabling reliable fabrication at smaller feature sizes while maintaining production efficiency

Inventive Principle:

Principle #10Preliminary action

2Productivity

If feature sizes continue to decrease to increase functional density, then production efficiency and cost are improved, but device reliability deteriorates

Engineering Contradiction:

Improveproduction efficiencyVSAvoiddevice reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The semiconductor protection layer is deposited in advance to shield source/drain regions and fin structures from damage during subsequent processing. This preliminary protection ensures device reliability is maintained even as feature sizes decrease and functional density increases

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protection layer acts as a cushioning barrier formed beforehand to absorb or prevent damage to critical semiconductor structures during etching and cleaning processes, thereby maintaining device reliability at scaled dimensions

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If a semiconductor protection layer with higher germanium concentration is applied to protect source/drain structures, then device reliability and performance are improved, but manufacturing complexity increases

Engineering Contradiction:

Improvedevice reliabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protection layer utilizes a higher germanium concentration parameter to achieve both protective function and carrier mobility enhancement. By changing the material composition parameter rather than adding separate protective structures, the solution improves reliability without significantly increasing manufacturing complexity

Inventive Principle:

Principle #35Parameter changes

4Reliability

If epitaxial source/drain structures are grown to enhance carrier mobility, then device performance is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvedevice performanceVSAvoidmanufacturing precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Epitaxial growth parameters are optimized to grow source/drain structures with specific crystal orientations and compositions that enhance carrier mobility. By precisely controlling growth parameters rather than relying on post-growth processing, high device performance is achieved while managing manufacturing precision requirements

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 improves the reliability and performance of FinFETs by protecting the source/drain structures from damage during processing and enhancing carrier mobility through strained structures, thereby overcoming the challenges of miniaturization in semiconductor device fabrication.

Implementation Method 1

a semiconductor protection layer is formed over the fin structure and the epitaxially grown source/drain structures

Methodology Applied

Scientific EffectPhysical barrier protection:

Implementation Method 2

enhancing carrier mobility through strained structures

Methodology Applied

Scientific EffectStrain effect:

Data Source

PatentUS9490346B2Structure and formation method of fin-like field effect transistor

Publication Date: 2016.11.08 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A structure and a formation method of a semiconductor device are provided. The semiconductor device includes a semiconductor substrate and a fin structure over the semiconductor substrate. The semiconductor device also includes a gate stack covering a portion of the fin structure and an epitaxially grown source/drain structure over the fin structure and adjacent to the gate stack. The semiconductor device further includes a semiconductor protection layer over the epitaxially grown source/drain structure. The semiconductor protection layer has an atomic concentration of germanium greater than that of the epitaxially grown source/drain structure.