FinFET Source/Drain Recess Cleaning for Crystal Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As the minimum feature sizes in semiconductor devices are reduced, challenges arise in forming recesses for epitaxial source/drain regions in FinFET devices, including contamination removal and reshaping of recesses to improve device performance.
Innovation Solution
A plasma cleaning process using hydrogen radicals is employed to remove contamination from the recess surfaces and reshape them, resulting in epitaxial source/drain regions with improved crystalline plane alignment and reduced dopant diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used to form recesses, then the recesses can be formed, but contamination remains on the recess surfaces and the crystalline plane alignment is poor
Solution Approach 1:
The patent changes the chemical parameters of the etching process by using a plasma-based etching process with specific gas compositions (CHF3, CF4, or SF6) and controlled process conditions. This parameter change enables both effective contamination removal and precise crystalline plane alignment in the formed recesses, resolving the contradiction between manufacturing precision and harmful factors.
Solution Approach 2:
The patent replaces conventional mechanical or chemical etching methods with a plasma-based etching process. The plasma process uses ion bombardment and chemical reactions to achieve superior surface cleaning and crystalline plane alignment, substituting the conventional approach with a more advanced physical-chemical process that simultaneously addresses both contamination and alignment issues.
2Productivity
If minimum feature sizes are reduced to increase integration density, then more components can be integrated, but additional fabrication challenges and contamination issues arise
Solution Approach 1:
The patent adjusts the etching process parameters including gas flow rates, pressure, and power levels to optimize the formation of smaller recesses with reduced feature sizes. By carefully controlling these parameters, the process maintains high precision and cleanliness even at smaller dimensions, enabling increased integration density without proportionally increasing fabrication challenges.
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 plasma cleaning process enhances the performance of FinFET devices by reducing electrical resistance, minimizing defects, and increasing on-state current, while also reducing unwanted dopant diffusion and leakage effects.
Implementation Method 1
A plasma cleaning process using hydrogen radicals is employed to remove contamination from the recess surfaces
Implementation Method 2
The plasma cleaning process using hydrogen radicals is employed to remove contamination from the recess surfaces and reshape them
Implementation Method 3
heating the holder to a process temperature between 300° C. and 1000° C.
Data Source
AI summary
A method includes forming a fin over a substrate, forming an isolation region adjacent the fin, forming a dummy gate structure over the fin, and recessing the fin adjacent the dummy gate structure to form a first recess using a first etching process. The method also includes performing a plasma clean process on the first recess, the plasma clean process including placing the substrate on a holder disposed in a process chamber, heating the holder to a process temperature between 300° C. and 1000° C., introducing hydrogen gas into a plasma generation chamber connected to the process chamber, igniting a plasma within the plasma generation chamber to form hydrogen radicals, and exposing surfaces of the recess to the hydrogen radicals. The method also includes epitaxially growing a source/drain region in the first recess.