Semiconductor Stressor Regions via Pre-Amorphous Implantation
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Solution Overview
Problem
Existing methods for forming stressor regions in semiconductor devices, such as MOSFETs, are not entirely satisfactory in enhancing carrier mobility and device performance, particularly at smaller technology nodes, due to limitations in controlling stress and strain distribution.
Innovation Solution
A method involving pre-amorphous implantation, stress film deposition, annealing, and epitaxial growth to create dislocations and strain-inducing regions in semiconductor devices, which includes a series of steps like PAI, stress film deposition, annealing, and epitaxial growth to form stressor regions that enhance carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing methods for forming stressor regions are used, then device fabrication can proceed with conventional processes, but carrier mobility and device performance are not sufficiently enhanced
Solution Approach 1:
The patent applies preliminary action by performing pre-amorphous implantation (PAI) before stress film deposition and annealing. This pre-treatment modifies the semiconductor substrate to prepare it for subsequent stressor formation, enabling better control over dislocation generation and stress distribution. The PAI step creates a controlled amorphous layer that facilitates predictable recrystallization and dislocation formation during the annealing process, thereby enhancing carrier mobility while maintaining process integration.
Solution Approach 2:
The patent utilizes parameter changes by precisely controlling annealing temperature, stress film thickness, and implantation conditions to optimize dislocation generation and stress distribution. By adjusting these parameters, the method achieves controlled formation of stressor regions that enhance carrier mobility. The stress film thickness and annealing temperature are specifically tuned to generate the desired density and distribution of dislocations, directly impacting device performance without requiring completely new fabrication processes.
2Reliability
If stressor regions are formed to enhance carrier mobility, then device performance improves, but control over stress and strain distribution becomes insufficient
Solution Approach 1:
The patent applies local quality by creating spatially varying stress distributions through controlled dislocation formation. The pre-amorphous implantation and subsequent annealing generate dislocations with specific density and distribution patterns in different regions of the semiconductor substrate. This enables localized stressor regions with tailored stress magnitudes and orientations, allowing precise control over strain distribution to enhance carrier mobility in specific device areas while maintaining overall process integration.
Solution Approach 2:
The patent uses the stress film as an intermediary element that mediates between the implantation process and the final stressor formation. The stress film deposited after PAI serves as a template and stress source that guides dislocation generation during annealing. This intermediary layer enables controlled transfer of stress to the semiconductor substrate, achieving precise stress distribution control and enhancing the ability to manipulate strain patterns for improved 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
This approach improves carrier mobility and device performance by creating controlled stress and strain in semiconductor devices, specifically increasing NMOS transistor performance by 10-25% through the formation of dislocations and strain in the channel region.
Implementation Method 1
performing a pre-amorphous implantation (PAI) process to form an amorphized region on a substrate
Implementation Method 2
performing an annealing process to recrystallize the amorphized region after the stress film is formed
Implementation Method 3
Stress distorts or strains the semiconductor crystal lattice, which affects the band alignment and charge transport properties of the semiconductor
Implementation Method 4
forming an epitaxial stress-inducing material in the recess region
Data Source
AI summary
A method of manufacturing a semiconductor device includes performing a pre-amorphous implantation (PAI) process to form an amorphized region on a substrate. The method also includes forming a stress film over the substrate, and performing an annealing process to recrystallize the amorphized region after the stress film is formed. The method further includes forming a recess region on the substrate. The recess region overlies the recrystallized region. The method additionally includes forming an epitaxial stress-inducing material in the recess region.