Fin-Shaped Structure Electrical Isolation via Oxide Layer
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Solution Overview
Problem
In modern multi-gate MOSFET processes, fin-shaped structures are incompletely electrically isolated due to insufficient dopant importation during ion implantation, leading to circuit leakage, which affects the integration and performance of semiconductor wafers.
Innovation Solution
A method is developed to form a fin-shaped structure by creating an oxide layer sandwiched between heterojunction fin structures and a substrate, with a liner formed on the sidewalls of the fin structures, allowing for complete electrical isolation and partial replacement of the fin structure with epitaxial layers to enhance electrical mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ion implantation process is used to form channel stop layers, then electrical isolation is achieved, but dopant importation is insufficient leading to circuit leakage
Solution Approach 1:
An oxide layer is introduced as an intermediary substance between the fin structure and the substrate. This oxide layer serves as a mediator that enhances electrical isolation by blocking charge carrier diffusion paths, compensating for the insufficient dopant importation from ion implantation processes.
Solution Approach 2:
The invention creates a composite structure combining the fin structure (silicon or III-V semiconductor), the oxide layer (silicon oxide or other dielectric), and the substrate. This composite material system provides superior electrical isolation properties compared to dopant-only approaches, effectively preventing circuit leakage.
2Reliability
If oxide layer is formed between fin structure and substrate, then complete electrical isolation is achieved, but manufacturing process complexity increases
Solution Approach 1:
The oxide layer is formed preliminarily between the fin structure and substrate before completing the fin structure fabrication. This preliminary action establishes the electrical isolation foundation early in the process, simplifying subsequent steps by eliminating the need for additional isolation corrections or adjustments.
Solution Approach 2:
The invention utilizes parameter changes in the oxidation process (temperature, time, atmosphere) to control the oxide layer thickness and properties. By adjusting these parameters, the process achieves complete electrical isolation while maintaining compatibility with existing manufacturing workflows, minimizing overall process complexity.
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 ensures complete electrical isolation of fin-shaped structures, reducing circuit leakage and improving electrical mobility, thereby enhancing the performance of semiconductor components.
Implementation Method 1
an oxide layer is formed between the fin structure and the substrate
Implementation Method 2
A buffer epitaxial layer and an epitaxial layer are sequentially formed in the recess
Data Source
AI summary
A method of forming a fin-shaped structure includes the following steps. A substrate having at least a fin structure thereon is provided. A liner is formed on sidewalls of the fin structure. An oxide layer is formed between the fin structure and the substrate. The fin structure is removed until a bottom layer of the fin structure is reserved, to form a recess between the liner. A buffer epitaxial layer and an epitaxial layer are sequentially formed in the recess. A top part of the liner is removed until sidewalls of the epitaxial layer are exposed. Moreover, a fin-shaped structure formed by said method is also provided.