FinFET Strained Channels via Ion Amorphization
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Solution Overview
Problem
Current FinFET device structures and fabrication methods face challenges in achieving enhanced carrier mobility and strain distribution, particularly in densely packed integrated circuits where traditional stressors become ineffective due to tight spacings and increased defects.
Innovation Solution
The method involves forming a fin with a recrystallized crystal structure incorporating internal strain by amorphizing a section of the fin using non-dopant ion implantation and subsequent annealing, which induces compressive or tensile strain in the channel, enhancing carrier mobility without introducing dopants or increasing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional stressors are used in densely packed integrated circuits, then device structure is simpler, but carrier mobility enhancement becomes ineffective due to tight spacings and increased defects
Solution Approach 1:
The fin is divided into distinct crystalline and amorphized sections through selective ion implantation. The amorphized section serves as a localized stressor region that transfers strain to the crystalline channel, enabling mobility enhancement without requiring traditional external stressor structures that would occupy valuable space in densely packed circuits.
Solution Approach 2:
The crystal structure of the fin material is changed from crystalline to amorphous in a specific section through ion implantation, then partially recrystallized through annealing to create a strained crystalline region. This parameter change in crystal structure enables internal strain generation without adding external stressor components.
2Reliability
If epitaxial semiconductor films are used as stressors, then carrier mobility is enhanced through induced stresses, but device complexity increases and spacing requirements increase
Solution Approach 1:
The stressor function is merged with the fin structure itself. The amorphized section of the fin acts as both the structural element and the stressor, eliminating the need for separate epitaxial stressor films. This integration reduces the overall device area and spacing requirements while maintaining the strain-induced mobility enhancement.
Solution Approach 2:
The stressor functionality is extracted from external epitaxial films and embedded within the fin structure through localized amorphization. This creates an internal stressor that eliminates the need for external stressor layers, reducing device area and simplifying the overall structure.
3Reliability
If non-dopant ion implantation is used to amorphize the fin, then carrier mobility is enhanced without introducing dopants, but manufacturing complexity increases
Solution Approach 1:
Non-dopant ions serve as an intermediary mechanism to induce amorphization and subsequent strain without directly doping the fin. The ions act as a temporary mediator that creates the desired crystal structure change and strain state, then can be removed or remain as neutral interstitials, achieving the mobility enhancement goal without introducing unwanted dopant contamination.
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 effectively increases carrier mobility and strain distribution in FinFETs, particularly in dense circuit designs where traditional stressors fail, by maintaining internal strain in the recrystallized section of the fin, thereby improving device performance without reliability issues.
Implementation Method 1
a section of the fin aligned with the opening is implanted with non-dopant ions to amorphize the first crystal structure of the semiconductor material of the fin
Implementation Method 2
the section of the fin is annealed such that the semiconductor material in the section of the fin recrystallizes with a second crystal structure incorporating internal strain
Implementation Method 3
maintaining internal strain in the recrystallized section of the fin, thereby improving device performance
Data Source
AI summary
Device structures for a fin-type field-effect transistor (FinFET) and methods for fabricating a device structure for a FinFET. A fin comprised of a semiconductor material having a first crystal structure is formed. A dielectric layer is formed that includes an opening aligned with the fin. A dummy gate structure is removed from the opening in the dielectric layer. After the dummy gate structure is removed, a section of the fin aligned with the opening is implanted with non-dopant ions to amorphize the first crystal structure of the semiconductor material of the fin. After the section of the fin is implanted, the section of the fin is annealed such that the semiconductor material in the section of the fin recrystallizes with a second crystal structure incorporating internal strain.