Fin Isolation Spacer Structure for Lower Parasitic Capacitance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The semiconductor industry faces challenges in reducing parasitic capacitance and preventing the growth of source/drain epitaxial features on side surfaces of well regions during the manufacturing of semiconductor device structures, which can lead to increased complexity and inefficiency in processing and manufacturing.
Innovation Solution
The implementation of shallow trench isolation (STI) protected by various layers, along with the use of spacer layers and mask structures, to prevent the growth of source/drain epitaxial features on side surfaces and reduce parasitic capacitance, is achieved through specific etching and deposition processes, including the formation of sacrificial gate structures and dielectric spacers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If source/drain epitaxial growth is performed on well regions, then source/drain regions are formed, but parasitic capacitance increases and current leakage occurs
Solution Approach 1:
The patent applies preliminary anti-action by forming a protective layer (such as oxide or nitride) on the well region surfaces before source/drain epitaxial growth. This protective layer prevents the epitaxial material from growing on the well region side surfaces, thereby preventing parasitic capacitance formation and current leakage paths before they can occur during the epitaxial growth process
Solution Approach 2:
The patent introduces an intermediary protective layer between the well regions and the source/drain epitaxial material. This intermediary layer (oxide, nitride, or other dielectric materials) acts as a barrier that allows the source/drain regions to form on the semiconductor surface while preventing unwanted epitaxial growth on the well region side surfaces, thus eliminating parasitic capacitance without affecting the formation of functional source/drain regions
2Productivity
If geometry size is scaled down, then production efficiency increases and costs decrease, but processing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-forming protective layers on well regions before the source/drain epitaxial growth process. This preliminary protection is integrated into the existing fabrication flow, allowing standard epitaxial growth conditions to be used without requiring additional complex processing steps, thereby maintaining production efficiency while managing processing complexity
Solution Approach 2:
The patent utilizes parameter changes in the protective layer materials (such as selecting oxide, nitride, or other dielectric materials with different etch selectivities and deposition properties) to optimize the process for scaled geometries. By adjusting material parameters and layer thicknesses, the patent enables effective parasitic capacitance prevention while maintaining compatibility with advanced fabrication processes
Data Source
AI summary
Embodiments of the present disclosure provide semiconductor device structures and methods of forming the same. The method includes depositing a spacer layer over an isolation region between adjacent fin structures, and the spacer layer is formed on sidewalls and tops of the fin structures. The method further includes forming a mask on the spacer layer between the fin structures, and the mask has a height substantially less than a height of the fin structures. The method further includes removing portions of the spacer layer and recessing the fin structures to form a spacer and to expose a portion of each fin structure, the spacer includes a first portion having a “U” shape disposed on the isolation region, and the portion of each fin structure has a top surface located at a level substantially below a top surface of the isolation region. The method further includes removing the mask.