Semiconductor Strained Material Particle Removal

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Solution Overview

Problem

The selective growth processes for strained structures in semiconductor devices often result in heterogeneous nucleation reactions, leading to particle formation on the gate stack and isolation regions, which can remain embedded and cause device instability and failure if not fully removed.

Innovation Solution

A method involving selective growth of silicon germanium in S/D recess cavities, followed by a strained-material protection layer, and a controlled etching process to fully remove particles while retaining the strained material, ensuring enhanced carrier mobility and device performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If selective growth process is used to form strained structures in S/D recess cavities, then carrier mobility is enhanced, but particles are formed on gate stack and isolation regions causing device instability

Engineering Contradiction:

Improvedevice stabilityVSAvoidparticle formation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful heterogeneous nucleation reactions that form particles into a beneficial process by having the strained material grow on top of the particles, encapsulating them within the strained structure. The particles become embedded within the strained material layer rather than remaining as surface contaminants, thus eliminating their harmful effects while maintaining the strain enhancement benefits

Inventive Principle:

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

Solution Approach 2:

The patent performs preliminary cleaning of the gate stack and isolation regions before the selective growth process to minimize particle formation. Additionally, the growth conditions are optimized in advance to reduce heterogeneous nucleation, and the strained material is grown to a sufficient thickness to ensure complete encapsulation of any particles that do form

Inventive Principle:

Principle #10Preliminary action

2Reliability

If selective growth process is used to form strained structures in S/D recess cavities, then device performance is improved, but particles remain embedded causing device failure

Engineering Contradiction:

Improvedevice performanceVSAvoidparticle removal completeness

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent transforms the particle contamination problem into a solution by using the strained material growth process to encapsulate particles within the strained structure. The particles become trapped inside the grown strained material layer, making them harmless and eliminating the need for aggressive cleaning that might damage the device structure

Inventive Principle:

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

Solution Approach 2:

The patent optimizes the growth parameters including temperature, pressure, and gas flow rates to control the selective growth process. By adjusting these parameters, the strained material grows at a controlled rate that ensures complete encapsulation of particles while maintaining high manufacturing precision and avoiding damage to surrounding structures

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If heterogeneous nucleation reactions occur during selective growth, then particles are formed on surfaces, but clean processes cannot fully remove them

Engineering Contradiction:

Improvecleaning process effectivenessVSAvoidembedded particles

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

Instead of attempting to remove particles through cleaning processes, the patent inverts the approach by having the strained material grow over and encapsulate the particles. This converts the cleaning problem into a encapsulation solution, making the particles harmless while avoiding the need for complex and potentially damaging cleaning steps

Inventive Principle:

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

Solution Approach 2:

The patent performs preliminary cleaning steps before the selective growth process to reduce the number of particles formed. The growth conditions are also optimized in advance to minimize heterogeneous nucleation, reducing the burden on subsequent cleaning processes

Inventive Principle:

Principle #10Preliminary action

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 effectively removes particles that could cause device instability, maintaining carrier mobility and upgrading device performance by ensuring the strained structure is free from embedded particles.

Implementation Method 1

selective growth of silicon germanium in source and drain (S/D) recess cavities

Methodology Applied

Scientific EffectSelective epitaxial growth: Epitaxy

Implementation Method 2

a strained-material protection layer is selectively grown on the strained material... a portion of the protection layer is removed

Methodology Applied

Scientific EffectEtching:

Data Source

PatentUS8377784B2Method for fabricating a semiconductor device

Publication Date: 2013.02.19 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

The present disclosure discloses an exemplary method for fabricating a semiconductor device comprises selectively growing a material on a top surface of a substrate; selectively growing a protection layer on the material; and removing a portion of the protection layer in an etching gas.