Nanostructure Transistor Trench Contact Liners for Higher Mobility

Solution Overview

Problem

Existing semiconductor devices face limitations in achieving enhanced charge carrier mobility and performance due to challenges in material interfaces and scattering effects.

Innovation Solution

The introduction of an enhanced semiconductor superlattice, referred to as MST technology, which incorporates alternating layers of semiconductor and non-semiconductor materials to reduce effective mass of charge carriers, improve interface quality, and act as a barrier to dopant diffusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional semiconductor structures are used, then manufacturing simplicity is maintained, but charge carrier mobility is limited due to scattering effects and interface quality issues

Engineering Contradiction:

Improvecharge carrier mobilityVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The semiconductor structure is divided into multiple alternating layers of different materials (e.g., Si/SiGe/Si) forming a superlattice. Each layer has specific thickness and composition designed to reduce scattering effects and improve interface quality, thereby enhancing charge carrier mobility without requiring complete redesign of the manufacturing process

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite material structures where alternating layers of semiconductor materials with different properties (e.g., silicon and silicon-germanium) are combined to create a superlattice. This composite structure exploits the beneficial properties of each material to reduce scattering and improve interface quality, achieving higher charge carrier mobility

Inventive Principle:

Principle #40Composite materials

2Reliability

If strained material layers are introduced to enhance mobility, then charge carrier mobility improves, but manufacturing precision requirements increase

Engineering Contradiction:

Improvecharge carrier mobilityVSAvoidlayer thickness control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent systematically varies parameters such as layer thickness, composition ratio, and strain magnitude in the alternating layers to optimize charge carrier mobility. By controlling these parameters within specific ranges, the design achieves enhanced mobility while maintaining compatibility with existing manufacturing precision capabilities

Inventive Principle:

Principle #35Parameter changes

3Reliability

If multiple alternating layers are formed to reduce scattering effects, then charge carrier mobility is enhanced, but device complexity increases

Engineering Contradiction:

Improvecharge carrier mobilityVSAvoidnumber of layers

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The semiconductor structure is divided into multiple alternating layers of different materials (e.g., Si/SiGe/Si) forming a superlattice. Each layer has specific thickness and composition designed to reduce scattering effects and improve interface quality, thereby enhancing charge carrier mobility without requiring complete redesign of the manufacturing process

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The alternating layer structure serves multiple functions simultaneously: it creates strain to enhance mobility, provides interfaces for scattering reduction, and maintains compatibility with standard manufacturing processes. This multi-functionality reduces the need for additional separate structures or processes

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 MST technology significantly enhances charge carrier mobility by reducing scattering effects and improving interface quality, leading to improved performance in semiconductor devices.

Implementation Method 1

The introduction of an enhanced semiconductor superlattice, referred to as MST technology, which incorporates alternating layers of semiconductor and non-semiconductor materials to reduce effective mass of charge carriers

Methodology Applied

Scientific EffectBand structure engineering:

Implementation Method 2

act as a barrier to dopant diffusion

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS12230694B2Method for making nanostructure transistors with source/drain trench contact liners

Publication Date: 2025.02.18 ATOMERA INC

AI summary

A method for making a semiconductor device may include forming spaced apart gate stacks on a substrate with adjacent gate stacks defining a respective trench therebetween. Each gate stack may include alternating layers of first and second semiconductor materials, with the layers of the second semiconductor material defining nanostructures. The method may further include forming respective source/drain regions within the trenches, respective insulating regions adjacent lateral ends of the layers of the first semiconductor material, and respective conductive contact liners in the trenches.