Source/Drain Lateral Growth Control via Mandrel Structure
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Solution Overview
Problem
The reduction in size of semiconductor devices leads to adjacent source/drains contacting each other due to excessive lateral growth, increasing resistance and reducing contact area, which affects their performance in mobile devices.
Innovation Solution
The semiconductor device design includes active fins with a gate structure crossing one region and source/drain disposed on another, where the source/drain has upper and vertical side surfaces parallel to the active fin, and an auxiliary contact layer surrounds the source/drain to prevent contact between adjacent source/drains, thereby controlling lateral growth and maintaining contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of semiconductor devices is reduced, then the device dimensions are minimized for mobile applications, but adjacent source/drains contact each other due to excessive lateral growth
Solution Approach 1:
A mandrel structure is formed beforehand in the source/drain region before crystal growth. This mandrel acts as a physical barrier that pre-defines the growth boundaries, preventing adjacent source/drains from contacting each other during lateral crystal growth while still allowing miniaturization of the device
2Area of stationary object
If source/drain lateral growth is allowed, then the contact area increases for better electrical connection, but adjacent source/drains contact each other causing increased resistance
Solution Approach 1:
The mandrel structure serves as an intermediary element between adjacent source/drain regions. It physically separates the growing crystal structures while allowing each source/drain to maintain adequate contact area with the gate electrode, thus preventing short circuits while ensuring good electrical connection
3Reliability
If the contact area between source/drain is maintained, then the electrical connection is improved, but the device size cannot be further reduced
Solution Approach 1:
The mandrel structure extends vertically into the source/drain region, utilizing the vertical dimension to provide separation between adjacent source/drains. This allows horizontal miniaturization of the device while maintaining adequate contact area through vertical confinement of the crystal growth
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 design suppresses lateral crystal growth, prevents contact between adjacent source/drains, reduces contact resistance, and enhances current driving capability by maintaining a sufficient contact area.
Implementation Method 1
A source/drain is formed on a second region of the active fin by crystal growth so that the source/drain includes upper surfaces and side surfaces. The side surfaces are in substantially parallel with side surfaces of the active fin.
Data Source
AI summary
According to an exemplary embodiment of the present embodiment, a semiconductor device is provided as follows. An active fin protrudes from a substrate, extending in a direction. A gate structure crosses a first region of the active fin. A source/drain is disposed on a second region of the active fin. The source/drain includes upper surfaces and vertical side surfaces. The vertical side surfaces are in substantially parallel with side surfaces of the active fin.