3D Ferroelectric Memory Stack with Templated Crystallization
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Solution Overview
Problem
Current ferroelectric memory devices face challenges in achieving high ferroelectric polarization and reliable data storage due to limitations in crystalline grain size and structural integrity of ferroelectric materials in three-dimensional memory devices.
Innovation Solution
The development of a ferroelectric memory device using a method of templated crystallization, where a crystalline template material like germanium or strontium titanium oxide is used to increase the crystalline grain size of ferroelectric materials like hafnium zirconium oxide, forming a vertical stack of discrete ferroelectric memory structures around a semiconductor channel, enhancing polarization and structural reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ferroelectric memory structures are used, then device fabrication is simpler, but the crystalline grain size is limited and polarization magnitude is insufficient
Solution Approach 1:
A crystalline template material layer is introduced as an intermediary between the ferroelectric material and the substrate. This template layer has a specific crystal structure that serves as a seed for the ferroelectric material to crystallize upon, thereby controlling and enhancing the crystalline grain size without requiring complex direct substrate interactions
Solution Approach 2:
The patent modifies the crystallization parameters of the ferroelectric material by controlling the template material layer's properties (such as crystal structure, thickness, and composition) to achieve larger crystalline grains and higher polarization magnitude while maintaining manufacturability
2Reliability
If ferroelectric material polarization is enhanced, then memory storage capability improves, but manufacturing complexity increases
Solution Approach 1:
The crystalline template material layer is formed in advance before depositing the ferroelectric material. This preliminary template structure pre-establishes the desired crystal orientation and grain size framework, making the subsequent ferroelectric material crystallization process more straightforward and controllable, thereby enhancing polarization without excessive manufacturing complexity
3Reliability
If crystalline grain size is increased, then electrical performance improves, but the manufacturing process becomes more complex
Solution Approach 1:
The template material acts as a mediator that translates the desired large crystalline grain structure into a controllable fabrication process. By depositing this intermediate layer with specific crystal properties, the subsequent ferroelectric material naturally crystallizes into larger grains during standard annealing processes, improving electrical performance without requiring complex direct crystallization control
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 significantly increases the magnitude of ferroelectric polarization and improves the electrical performance and reliability of the memory devices by promoting larger crystal grain sizes in the ferroelectric materials, leading to superior data storage capabilities.
Implementation Method 1
converting the dielectric material portions into crystalline ferroelectric material portions by performing an anneal process
Implementation Method 2
converting the dielectric material portions into crystalline ferroelectric material portions by performing an anneal process
Data Source
AI summary
A ferroelectric memory device includes an alternating stack of insulating layers and electrically conductive layers, a memory opening extending vertically through the alternating stack and including laterally-protruding portions at levels of the electrically conductive layers, and a memory opening fill structure located in the memory opening and containing a vertical semiconductor channel and a vertical stack of discrete ferroelectric memory structures located in the laterally-protruding portions of the memory opening. Each of the ferroelectric memory structures includes crystalline ferroelectric material portion and a crystalline template material portion located between a respective electrically conductive layer of the electrically conductive layers and the crystalline ferroelectric material portion.