FinFET Source/Drain Carbon Buffer Layer for Dopant Diffusion Control
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Solution Overview
Problem
As semiconductor devices, such as FinFETs, undergo miniaturization, they face challenges in reducing resistance and improving channel mobility due to dopant diffusion from source/drain regions into the channel region, affecting device performance and reliability.
Innovation Solution
Incorporating a carbon buffer layer in the source/drain regions to prevent dopant diffusion, which is achieved through epitaxial growth of carbon-doped silicon layers, reducing resistance and enhancing channel mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If minimum feature size is reduced to improve integration density, then more components can be integrated into a given area, but dopant diffusion from source/drain regions into the channel region increases, degrading device performance
Solution Approach 1:
The source/drain region is segmented into multiple distinct layers: a first doped semiconductor layer, a carbon-containing buffer layer, and a second doped semiconductor layer. This segmentation prevents dopant diffusion into the channel by inserting the carbon-containing buffer layer between the doped regions and the channel, thereby maintaining device performance while enabling continued miniaturization for higher integration density.
Solution Approach 2:
A carbon-containing buffer layer is introduced as an intermediary between the doped semiconductor layers and the channel region. This buffer layer acts as a diffusion barrier that blocks dopant atoms from migrating into the channel, thus preventing performance degradation while allowing the device to benefit from reduced feature sizes and improved integration density.
2Loss of energy
If source/drain dopant concentration is increased to reduce resistance, then conductivity improves, but dopant diffusion into the channel region increases, reducing channel mobility
Solution Approach 1:
The source/drain structure is divided into multiple layers with a carbon-containing buffer layer positioned between the doped semiconductor layers and the channel. This segmentation allows high dopant concentration in the source/drain regions to reduce resistance while the buffer layer prevents dopant migration into the channel, thereby preserving channel mobility.
Solution Approach 2:
The carbon-containing buffer layer serves as an intermediary barrier that enables high dopant concentration in the source/drain regions without compromising channel mobility. The buffer layer blocks dopant diffusion into the channel while allowing the high dopant concentration in the source/drain regions to effectively reduce resistance and energy loss.
3Productivity
If feature size is reduced to improve integration density, then manufacturing area is optimized, but manufacturing precision requirements increase due to dopant diffusion control challenges
Solution Approach 1:
The source/drain region is segmented into multiple layers including a carbon-containing buffer layer. This segmentation provides an inherent diffusion barrier that simplifies manufacturing precision requirements, as the buffer layer physically prevents dopant diffusion into the channel even when feature sizes are reduced for higher integration density.
Solution Approach 2:
The carbon-containing buffer layer acts as an intermediary that eliminates the need for extremely precise manufacturing control to prevent dopant diffusion. By introducing this buffer layer, the patent enables reduced feature sizes for improved integration density without increasing manufacturing precision requirements, as the buffer layer passively blocks dopant migration.
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 carbon buffer layer effectively reduces dopant diffusion, leading to improved performance and reliability of FinFET devices by maintaining source/drain dopants out of the channel region, thus enhancing channel mobility and device efficiency.
Implementation Method 1
epitaxial growth of carbon-doped silicon layers
Data Source
AI summary
An embodiment includes a device including a first fin extending from a substrate. The device also includes a first gate stack over and along sidewalls of the first fin. The device also includes a first gate spacer disposed along a sidewall of the first gate stack. The device also includes a first source/drain region in the first fin and adjacent the first gate spacer, the first source/drain region including a first carbon-containing buffer layer on the first fin. The device also includes and a first epitaxial structure on the first carbon-containing buffer layer.