3D Memory Devices With TMD Channels
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Solution Overview
Problem
Conventional 3D memory devices with poly-silicon channels suffer from low mobility and reduced current due to ungated channel regions, limiting their performance and read speed.
Innovation Solution
The use of transition metal dichalcogenide (TMD) channels in 3D memory devices, such as ferroelectric field-effect transistors, which provide higher mobility and faster bitcells by reducing grain boundaries and making the material more conductive, along with doped or metallic source/drain regions and low-resistance access regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If poly-silicon channels are used in conventional 3D memory devices, then device structure is simpler to manufacture, but channel mobility is low and current flow is reduced
Solution Approach 1:
The patent changes the material parameter from poly-silicon to transition metal dichalcogenide (TMD) to fundamentally improve channel mobility. This material substitution transforms the electrical properties of the channel, enabling higher carrier mobility and faster device operation while maintaining compatibility with existing 3D memory fabrication processes
Solution Approach 2:
The patent employs composite material structures including TMD channels combined with doped or metallic source/drain regions, and integrates multiple functional layers such as ferroelectric layers and tunnel oxide layers. This composite approach optimizes both electrical performance and manufacturability by combining materials with complementary properties
2Speed
If conventional poly-silicon channels are used, then device structure is simpler, but read speed is slower due to ungated channel regions
Solution Approach 1:
The patent changes the channel material parameter to TMD, which inherently provides higher mobility and enables faster read speeds. The material's superior electrical properties allow for reduced channel resistance and improved carrier transport, directly addressing the speed limitation of conventional poly-silicon channels
Solution Approach 2:
The patent applies local quality optimization by introducing doped or metallic source/drain regions specifically at the source and drain contacts, while maintaining the TMD channel in the gate-controlled region. This localized modification reduces contact resistance and enhances current flow without complicating the overall device structure
3Productivity
If TMD channels with doped or metallic source/drain regions are used, then current flow and mobility are enhanced, but manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by forming the TMD channel layer early in the fabrication sequence, before subsequent deposition of ferroelectric and oxide layers. The doped or metallic source/drain regions are also prepared in advance through selective doping or deposition processes, enabling optimized current flow from the outset without requiring complex post-processing steps
Solution Approach 2:
The patent uses intermediary materials and processes such as tunnel oxide layers and ferroelectric layers that mediate between the TMD channel and the control gate, enabling precise control over the channel properties while maintaining manufacturing feasibility. These intermediary layers facilitate the integration of TMD channels into existing 3D memory fabrication workflows
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 TMD channels enhance channel mobility and current flow, leading to improved performance and faster read speeds compared to conventional devices, enabling increased capacity and efficiency in memory devices.
Implementation Method 1
The use of transition metal dichalcogenide (TMD) channels in 3D memory devices, such as ferroelectric field-effect transistors, which provide higher mobility and faster bitcells by reducing grain boundaries and making the material more conductive
Implementation Method 2
along with doped or metallic source/drain regions and low-resistance access regions
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Embodiments of the disclosure are directed to advanced integrated circuit structure fabrication and, in particular, to three-dimensional (3D) memory devices with transition metal dichalcogenide (TMD) channels. Other embodiments may be disclosed or claimed.