FinFET Epitaxy Structure With Graded Germanium Source/Drain Regions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices face challenges in forming efficient source and drain regions in finFETs, particularly in achieving optimal carrier mobility and device performance.
Innovation Solution
The formation of epitaxy source and drain regions using a germanium-containing epitaxy structure with a specific germanium atomic percentage profile and boron concentration profile, which is grown in a recess on the semiconductor fin, enhances carrier mobility and device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional source/drain regions are formed in finFETs, then device structure is simple, but carrier mobility and device performance are insufficient
Solution Approach 1:
The patent applies local quality by creating epitaxial source and drain regions with spatially varying germanium concentrations. The first portion has a higher germanium atomic percentage than the second portion, with each portion having different concentration profiles. This non-uniform composition optimizes carrier mobility in the channel region while maintaining structural integrity and reducing defects at interfaces.
Solution Approach 2:
The patent uses composite materials by forming epitaxial structures that combine silicon with varying germanium concentrations. The source/drain regions consist of multiple epitaxial portions with different germanium atomic percentages, creating a composite structure that leverages the beneficial properties of each composition zone to enhance overall device performance.
2Reliability
If germanium-containing epitaxy structure is formed with optimized profiles, then carrier mobility improves, but manufacturing process complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the epitaxial source and drain regions into multiple distinct portions, each with specific germanium concentration ranges and profiles. The first portion has a higher germanium atomic percentage with its own concentration profile, while the second portion has a lower germanium atomic percentage with a different profile. This segmentation allows precise control of carrier mobility in each region while managing manufacturing complexity through modular process design.
3Reliability
If epitaxial structures with varying germanium concentrations are formed, then contact resistance reduces, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by systematically varying the germanium atomic percentage across different epitaxial portions and their profiles. The first portion has a higher germanium concentration with a specific profile, while the second portion has a lower concentration with a different profile. These controlled parameter variations optimize electrical properties including contact resistance, while the defined ranges and profiles provide clear manufacturing targets for process control.
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 carrier mobility and enhances the performance of semiconductor devices by forming epitaxy structures with optimized germanium and boron profiles, facilitating better source/drain contact formation and reduced contact resistance.
Implementation Method 1
The formation of epitaxy source and drain regions using a germanium-containing epitaxy structure with a specific germanium atomic percentage profile and boron concentration profile, which is grown in a recess on the semiconductor fin
Data Source
AI summary
A semiconductor device includes a substrate, at least one semiconductor fin, and at least one epitaxy structure. The semiconductor fin is present on the substrate. The semiconductor fin has at least one recess thereon. The epitaxy structure is present in the recess of the semiconductor fin. The epitaxy structure includes a topmost portion, a first portion and a second portion arranged along a direction from the semiconductor fin to the substrate. The first portion has a germanium atomic percentage higher than a germanium atomic percentage of the topmost portion and a germanium atomic percentage of the second portion.