3D Ferroelectric Memory Stacks Using Oxygen-Deficient Alloy Layers
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Solution Overview
Problem
Current three-dimensional memory devices face challenges in effectively utilizing ferroelectric materials for data storage due to limitations in the integration and control of ferroelectric elements within the memory structure, leading to inefficiencies in data retention and processing.
Innovation Solution
The development of a semiconductor memory device with a vertical stack of discrete ferroelectric material portions formed by alloying first and second dielectric metal oxide materials, integrated within an alternating stack of insulating and conductive layers, and the use of oxygen-gettering liners to create non-stoichiometric oxygen-deficient ferroelectric material portions, enhancing data storage capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ferroelectric materials are integrated into three-dimensional memory structures, then memory capacity and density are improved, but integration complexity and manufacturing difficulty increase
Solution Approach 1:
The ferroelectric material is divided into discrete portions arranged in vertical stacks within memory openings, rather than using continuous layers. This segmentation enables precise control of ferroelectric material placement and integration with conductive layers at specific levels, reducing integration complexity while maintaining high memory capacity through three-dimensional stacking
Solution Approach 2:
The patent transitions from two-dimensional planar memory structures to three-dimensional vertical structures by forming vertical stacks of ferroelectric material portions extending through alternating insulating and conductive layers. This dimensional change increases memory capacity per unit area while the modular stack architecture manages integration complexity
2Ease of manufacture
If conventional ferroelectric material deposition methods are used, then manufacturing process is simpler, but material composition control and oxygen stoichiometry are insufficient
Solution Approach 1:
The patent employs atomic layer deposition (ALD) to precisely control the composition and oxygen stoichiometry of ferroelectric metal oxide materials by adjusting deposition parameters such as precursor flow rates, temperature, and cycle numbers. This enables accurate control of metal-to-oxygen ratios to achieve desired ferroelectric properties while maintaining a manufacturable process
Solution Approach 2:
The patent replaces conventional physical vapor deposition methods with chemical vapor deposition (ALD), substituting a chemically-controlled deposition mechanism for physically-driven processes. This enables atomic-level precision in composition control through self-limiting surface reactions, achieving superior manufacturing precision while remaining scalable
3Reliability
If oxygen-deficient ferroelectric materials are formed through alloying, then ferroelectric performance is improved, but additional processing steps increase manufacturing complexity
Solution Approach 1:
The patent combines multiple functions into the alloying process: forming the ferroelectric material composition, creating oxygen deficiency for enhanced ferroelectric performance, and establishing vertical stacking architecture all through an integrated thermal annealing process. This merging of functions achieves superior ferroelectric performance without proportionally increasing processing complexity
Solution Approach 2:
The patent uses controlled thermal annealing parameters (temperature, atmosphere composition, duration) to simultaneously achieve oxygen diffusion, alloy formation, and oxygen deficiency creation. By optimizing these parameters, the process creates oxygen-deficient ferroelectric materials with enhanced performance while keeping the processing step count manageable through parameter optimization rather than additional steps
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 improves data storage efficiency, scalability, and reduces power consumption by forming discrete ferroelectric layers that enhance memory window size and endurance, while simplifying the integration process and eliminating the need for precise dopant control.
Implementation Method 1
forming a vertical stack of discrete ferroelectric material portions by depositing a second dielectric metal oxide layer comprising a second dielectric metal oxide material in the backside recesses and alloying the second dielectric metal oxide material and the first dielectric metal oxide material at interfaces between the first dielectric metal oxide layer and the second dielectric metal oxide layer
Implementation Method 2
forming a vertical stack of discrete non-stoichiometric oxygen-deficient ferroelectric material portions and a vertical semiconductor channel, wherein: the discrete non-stoichiometric oxygen-deficient ferroelectric material portions are vertically spaced apart from each other; and each of the discrete non-stoichiometric oxygen-deficient ferroelectric material portions is in direct contact with a sidewall of a respective oxygen-gettering liner
Data Source
AI summary
A semiconductor memory device includes an alternating stack of insulating layers and electrically conductive layers, a memory opening vertically extending through the alternating stack, and a memory opening fill structure located in the memory opening and including a vertical stack of discrete ferroelectric material portions and a vertical semiconductor channel. In one embodiment, the discrete ferroelectric material portions include a ferroelectric alloy material of a first dielectric metal oxide material and a second dielectric metal oxide material. In another embodiment, each of the discrete ferroelectric material portions is oxygen-deficient.