Fin Structure Formation via Two-Step Implantation
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Solution Overview
Problem
Conventional FinFET device fabrication methods face challenges in forming defect-free fin structures, as hot implant processes can introduce cluster defects and exceed thermal budgets, especially in low dosage situations.
Innovation Solution
A two-step implantation process is employed, involving a hot implantation process at elevated temperatures to form a crystal fin seed, followed by a cryo implantation process at low temperatures to create a globally amorphous region, which is then recrystallized via spike annealing, reducing cluster defects and maintaining thermal budget constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hot implant process is used to remove twin-like defects, then the fin structure quality is improved, but cluster defects are induced and thermal budget is exceeded
Solution Approach 1:
The implantation process is divided into two separate steps: a hot implantation step to form the fin seed and remove twin-like defects, followed by a cryo implantation step to eliminate cluster defects. This segmentation allows each step to be optimized for its specific function without the trade-offs of a single process
Solution Approach 2:
The implantation process utilizes drastic temperature parameter changes - from elevated temperatures during hot implantation to cryogenic temperatures during cold implantation. This parameter change enables the same implantation mechanism to produce different structural outcomes, eliminating defects at both hot and cold phases
2Reliability
If a hot implant process is used to remove twin-like defects, then the fin structure quality is improved, but thermal budget is exceeded
Solution Approach 1:
The process employs periodic temperature action - alternating between hot implantation at elevated temperatures and cryo implantation at cryogenic temperatures. This periodic thermal action allows the system to benefit from high-temperature defect removal while subsequently resetting the thermal state to prevent budget exhaustion
Solution Approach 2:
The process exploits phase transitions in the silicon lattice - using hot implantation to create crystalline order, then cryo implantation to create amorphous regions that are subsequently recrystallized. This phase transition approach allows defect removal without sustained high-temperature exposure that would consume thermal budget
3Temperature
If low dosage implantation is used, then thermal budget is maintained, but cluster defects are induced
Solution Approach 1:
The dosage parameter is changed between the two implantation steps - using lower dosage during hot implantation to form the seed, then adjusting dosage during cryo implantation to achieve complete amorphization without cluster defects. This parameter adjustment allows thermal budget maintenance while preventing cluster defect formation
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 two-step implantation process effectively eliminates cluster defects and ensures full recrystallization of the fin structure, improving the quality of FinFET devices while adhering to thermal budget limitations.
Implementation Method 1
performing a first implantation process to a region of the fin structure to form a fin seed within the region of the fin structure
Implementation Method 2
the fin seed has a crystal structure
Implementation Method 3
performing a second implantation process to the region of the fin structure to cause the region of the fin structure outside the fin seed to become amorphous
Implementation Method 4
cause the region of the fin structure outside the fin seed to become amorphous
Implementation Method 5
performing an annealing process to recrystallize the region of the fin structure via the fin seed
Implementation Method 6
spike annealing
Data Source
AI summary
The present disclosure discloses a method of fabricating a semiconductor device. A fin structure is formed over a substrate. The fin structure contains a semiconductor material. A first implantation process is performed to a region of the fin structure to form a fin seed within the region of the fin structure. The fin seed has a crystal structure. The first implantation process is performed at a process temperature above about 100 degrees Celsius. A second implantation process is performed to the region of the fin structure to cause the region of the fin structure outside the fin seed to become amorphous. The second implantation process is performed at a process temperature below about 0 degrees Celsius. Thereafter, an annealing process is performed to recrystallize the region of the fin structure via the fin seed.