FinFET Buffer Layer Recesses for Epitaxial Fin Growth
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Solution Overview
Problem
Current FinFET manufacturing processes face challenges in efficiently forming fins and achieving uniformity, as they often require direct growth on substrates, leading to complex and costly procedures.
Innovation Solution
A method involving the formation of a buffer layer with recesses beneath isolation structures and fins, allowing the fin to be grown epitaxially within these recesses, simplifying the process and improving uniformity by forming the buffer layer before the fins, using specific etching gases and materials like Ge, SiGe, and InAs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fins are grown directly on substrates, then fin formation is achieved, but the manufacturing process becomes complex and costly
Solution Approach 1:
A buffer layer is formed over the substrate before fin formation. This preliminary action simplifies the overall manufacturing process by providing a prepared surface for subsequent fin growth, eliminating the need for complex direct-on-substrate fin formation procedures.
Solution Approach 2:
The buffer layer acts as an intermediary between the substrate and the fin structure. This intermediate layer facilitates easier fin formation and provides a controlled interface that simplifies the manufacturing process while maintaining device performance.
2Manufacturing precision
If a buffer layer is formed before fins, then uniformity is improved, but additional process steps are required
Solution Approach 1:
The buffer layer is formed in advance to establish a uniform base for fin growth. This preliminary preparation ensures consistent fin uniformity across the wafer, with the buffer layer providing a controlled surface that promotes homogeneous material properties and reduces variability in fin dimensions.
3Manufacturing precision
If recesses are formed in the buffer layer, then fin growth control is improved, but process complexity increases
Solution Approach 1:
The buffer layer is selectively removed to form recesses at specific locations where fins will be grown. This local modification provides precise control over fin growth positioning and depth, creating tailored conditions in the recess areas while maintaining the buffer layer elsewhere to support overall uniformity.
Solution Approach 2:
The recesses introduce a vertical dimension variation in the buffer layer thickness, allowing control of fin growth depth and positioning. By creating depth variations in the buffer layer, the process achieves precise fin growth control without requiring complex lateral patterning or additional constraint structures.
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 simplifies the FinFET formation process, enhances fin growth ease, and improves performance by allowing the buffer layer to provide uniformity and support for the fin, reducing complexity and cost.
Implementation Method 1
allowing the fin to be grown epitaxially within these recesses
Implementation Method 2
a portion of the insulating layer is removed, so as to form a trench penetrating the insulating layer. By using the insulating layer having the trench as a mask, a portion of the buffer layer is removed
Data Source
AI summary
A FinFET and a method of forming the same are provided. The FinFET includes a substrate, a buffer layer, an insulating layer, a fin and a gate. A buffer layer is disposed over the substrate, and includes a recess without penetrating the buffer layer. The insulating layer is disposed over the buffer layer, and includes a plurality of isolation structures and a trench between the isolation structures. The fin is disposed in the recess of the buffer layer and the trench of the insulating layer. The gate is disposed across the fin.