Semiconductor Device With Dislocation-Based Tensile Stress
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Solution Overview
Problem
Existing approaches to forming stressor regions in semiconductor devices, such as MOSFETs, are inadequate in enhancing carrier mobility and device performance, particularly for NMOS transistors, as they do not effectively utilize dislocations to create sufficient tensile stress in the channel region.
Innovation Solution
A semiconductor device structure is developed with epitaxial layers containing dislocations, specifically a first dislocation with a reverse V-shaped profile and a second dislocation with a V-shaped profile, both contributing to tensile stress in the channel region, improving carrier mobility by forming these dislocations within the epitaxial layer and adjacent to the surface, respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing approaches to forming stressor regions are used, then device structure is maintained, but carrier mobility enhancement is insufficient
Solution Approach 1:
The stressor region is segmented into multiple discrete dislocations with specific profiles (reverse V-shaped and V-shaped) rather than using a continuous stressor structure. This segmentation allows precise control over stress distribution to enhance carrier mobility while managing structural complexity
Solution Approach 2:
Different dislocation profiles (reverse V-shaped for first dislocations, V-shaped for second dislocations) are used in different locations within the epitaxial layer to create localized stress patterns optimized for carrier mobility enhancement in specific regions of the channel
2Reliability
If dislocations are formed only within the epitaxial layer, then stress distribution is limited, but carrier mobility enhancement is insufficient
Solution Approach 1:
The stressor structure extends from a single plane within the epitaxial layer into a three-dimensional configuration with dislocations positioned at different depths and orientations. This dimensional expansion creates more comprehensive stress distribution throughout the channel region, increasing tensile stress magnitude to enhance carrier mobility
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 described structure enhances carrier mobility and device performance by creating effective tensile stress in the channel region, particularly benefiting NMOS transistors, while maintaining compatibility with existing manufacturing processes.
Implementation Method 1
The dislocations in the source and drain regions and the tensile stress created by the doped epitaxial materials next to the channel region of a transistor both contribute to the tensile stress in the channel region
Data Source
AI summary
The present invention provides a semiconductor device, including a substrate, two gate structures disposed on a channel region of the substrate, an epitaxial layer disposed in the substrate between two gate structures, a first dislocation disposed in the epitaxial layer, wherein the profile of the first dislocation has at least two non-parallel slanting lines, and a second dislocation disposed adjacent to a top surface of the epitaxial layer, and the profile of the second dislocation has at least two non-parallel slanting lines.