FinFET Embedded Nonvolatile Memory Fabrication via Dummy Gate
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Solution Overview
Problem
The existing methods for fabricating embedded nonvolatile memory (eNVM) devices are not fully compatible with current FinFET processes, limiting their performance and integration with advanced transistor structures.
Innovation Solution
A method involving the formation of a semiconductor substrate with fin bodies, a charge storage layer, inter-layer dielectric polishing, recess etching, and the deposition of a high-k dielectric layer, where the remnant dummy gate layer acts as a charge storage medium, and a word line is formed, enabling compatibility with FinFET processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing methods are used to fabricate embedded nonvolatile memory, then the fabrication process can be completed, but the process is not fully compatible with current FinFET processes, limiting performance and integration
Solution Approach 1:
The dummy gate layer is assigned dual functionality: it serves as both the structural gate element during FinFET fabrication and as the charge storage layer for nonvolatile memory operation. This multi-functional approach enables the same structure to fulfill both process compatibility and memory functionality requirements
Solution Approach 2:
The existing dummy gate layer, which would otherwise be a non-functional byproduct of the FinFET fabrication process, is repurposed to serve as the charge storage medium. This self-service approach eliminates the need for separate charge storage layer deposition steps, achieving full process compatibility
2Adaptability or versatility
If a charge storage layer is added to enable nonvolatile memory functionality, then memory functionality is achieved, but the process complexity increases and compatibility with FinFET processes decreases
Solution Approach 1:
The gate structure and charge storage layer are merged into a single integrated structure. The dummy gate layer simultaneously provides both the gate function required for FinFET operation and the charge storage function required for nonvolatile memory, eliminating the need for separate layers and reducing fabrication complexity
Solution Approach 2:
The high-k dielectric layer acts as an intermediary between the control gate and the charge storage function, enabling effective charge trapping and retention while maintaining electrical isolation and compatibility with standard FinFET fabrication processes
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 method allows for the fabrication of eNVM devices that are fully compatible with FinFET processes, enhancing performance and integration by utilizing the polysilicon dummy gate layer as a charge storage medium and incorporating a high-k dielectric layer, thus improving the functionality of eNVM cells.
Implementation Method 1
The inter-layer dielectric layer is polished to expose a top surface of the charge storage layer
Implementation Method 2
The charge storage layer is then recess etched and cut into separate charge storage structures
Implementation Method 3
A high-k dielectric layer is formed on the charge storage structures
Data Source
AI summary
A method of fabricating an embedded nonvolatile memory device is disclosed. A semiconductor substrate having thereon a fin body protruding from an isolation layer is provided. A charge storage layer crossing the fin body is formed. An inter-layer dielectric layer is deposited on the semiconductor substrate. The inter-layer dielectric layer is polished to expose a top surface of the charge storage layer. The charge storage layer is then recess etched and cut into separate charge storage structures. A high-k dielectric layer is formed on the charge storage structures. A word line is formed on the high-k dielectric layer.