Oxygen-Doped Source/Drain Epitaxy for FinFET Diffusion Control
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Solution Overview
Problem
The challenge in semiconductor devices is to maintain high integration density and improve electrical properties while preventing impurity diffusion and short channel effects, especially in FinFET structures with reduced feature sizes.
Innovation Solution
Incorporating an oxygen-doped barrier layer between epitaxial layers in the source/drain regions of semiconductor devices, which forms a superlattice structure to prevent impurity diffusion and enhance charge mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the feature size of FinFET is reduced to increase integration density, then integration density is improved, but impurity diffusion and short channel effects worsen
Solution Approach 1:
The source/drain region is divided into multiple epitaxial layers with different impurity concentrations, creating a graded structure that segments the impurity distribution. This segmentation prevents abrupt impurity diffusion while maintaining the reduced feature size needed for high integration density.
Solution Approach 2:
An intermediate barrier layer is introduced between the high-doped and low-doped epitaxial layers. This intermediary layer acts as a diffusion barrier that prevents impurity migration, resolving the contradiction between maintaining fine feature sizes and preventing impurity diffusion.
2Productivity
If the feature size of FinFET is reduced to increase integration density, then integration density is improved, but short channel effects worsen
Solution Approach 1:
Different regions of the source/drain structure are assigned different impurity concentrations through multiple epitaxial layers. The high-doped region near the contact provides good electrical contact, while the low-doped region near the channel reduces short channel effects, achieving local optimization of electrical properties.
Solution Approach 2:
The impurity concentration parameter is gradually changed across multiple epitaxial layers rather than being uniform. This parameter gradient allows the structure to maintain electrical conductivity while reducing the abrupt doping profiles that cause short channel effects in scaled devices.
3Reliability
If multiple epitaxial layers with different impurity concentrations are formed, then electrical properties are improved, but manufacturing complexity increases
Solution Approach 1:
The multiple epitaxial layers with different impurity concentrations are formed in advance during the epitaxial growth process, before subsequent manufacturing steps. This preliminary formation of the graded structure simplifies later processing by establishing the optimal impurity profile early in the manufacturing sequence.
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 oxygen-doped barrier layer effectively prevents impurity diffusion, maintaining device performance and enhancing charge mobility, thus improving the electrical properties of semiconductor devices.
Implementation Method 1
a first barrier layer between the first epitaxial layer and the second epitaxial layer, wherein the first barrier layer comprises doped oxygen
Data Source
AI summary
A semiconductor device includes: an active region extending on a substrate in a first direction; a gate structure intersecting the active region and extending on the substrate in a second direction; and a source/drain region on the active region on at least one side of the gate structure. The source/drain region may include a first epitaxial layer on the active region and including impurities of a first conductivity type in a first concentration, a second epitaxial layer on the first epitaxial layer and including the impurities of the first conductivity type in a second concentration, and a first barrier layer between the first epitaxial layer and the second epitaxial layer, wherein the first barrier layer includes doped oxygen.