FeRAM Perovskite Capacitor Etching for High-Density Arrays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ferroelectric Random Access Memory (FeRAM) devices face challenges in achieving high density due to non-vertical etch profiles and residue accumulation during ion beam etching, leading to device degradation and limited aspect ratios.
Innovation Solution
The use of non-lead based perovskite materials and reactive ion etching techniques with specific gas chemistries, such as Ar, N2, O2, HBr, or CH4, to pattern FeRAM devices, enabling residue-free sidewalls and higher aspect ratios, thereby facilitating the fabrication of high-density arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ion beam etching is used to pattern ferroelectric materials, then etching capability is achieved, but non-vertical profiles and etch residue are generated causing device degradation
Solution Approach 1:
The patent changes the etching parameters by switching from ion beam etching to reactive ion etching with specific gas chemistries (Ar, N2, O2, HBr, or CH4). This parameter change transforms the etching mechanism to achieve both effective material removal and vertical profiles with minimal residue, resolving the contradiction between etching capability and profile precision.
Solution Approach 2:
The patent replaces the mechanical ion beam etching process with a chemical-based reactive ion etching process. This substitution uses chemical reactions between etch gases and ferroelectric materials to achieve cleaner, more precise etching with vertical sidewalls, eliminating the mechanical damage and residue issues of ion beam etching.
2Ease of manufacture
If ion beam etching is used to pattern ferroelectric materials, then etching capability is achieved, but etch residue accumulation causes device degradation
Solution Approach 1:
The patent changes the etching parameters by adopting reactive ion etching with optimized gas chemistries (Ar, N2, O2, HBr, or CH4). This parameter change enables complete removal of etch residue through enhanced chemical reactions, eliminating the harmful residue accumulation while maintaining effective etching capability.
Solution Approach 2:
The patent replaces mechanical ion beam etching with chemical reactive ion etching. This substitution fundamentally changes the removal mechanism from physical sputtering to chemical reaction, which produces volatile byproducts that are easily removed, thereby eliminating residue accumulation and device degradation.
3Device complexity
If conventional etching methods are used, then fabrication process is simple, but aspect ratio is limited preventing high density arrays
Solution Approach 1:
The patent changes the etching process parameters to reactive ion etching with specific gas chemistries, which enables the formation of high aspect ratio structures with vertical sidewalls. This parameter change allows the fabrication of tall, narrow capacitor structures necessary for high density arrays while maintaining a controlled and reproducible fabrication process.
Solution Approach 2:
The patent employs a multi-step reactive ion etching process with periodic gas chemistry changes (Ar, N2, O2, HBr, or CH4) to progressively achieve the desired high aspect ratio profile. This periodic action allows precise control over the etching process, enabling the formation of complex high aspect ratio structures while maintaining process simplicity through systematic step management.
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 allows for the creation of FeRAM devices with greater than 5:1 aspect ratios, reducing residue accumulation and improving device density, while maintaining environmental friendliness and performance.
Implementation Method 1
reactive ion etching techniques with specific gas chemistries, such as Ar, N2, O2, HBr, or CH4, to pattern FeRAM devices, enabling residue-free sidewalls and higher aspect ratios
Data Source
AI summary
Non lead-based perovskite ferroelectric devices for high density memory and logic applications and methods of fabrication are described. While various embodiments are described with reference to FeRAM, capacitive structures formed herein can be used for any application where a capacitor is desired. For example, the capacitive structure can be used for fabricating ferroelectric based or paraelectric based majority gate, minority gate, and/or threshold gate.