Barium Titanate Film Crystallization for Low-Temperature BEOL Integration
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Solution Overview
Problem
Current methods for producing high-crystallinity barium titanate films require high temperatures, making them unsuitable for back-end-of-line integration processes in non-volatile memory devices.
Innovation Solution
A method involving atomic layer deposition of barium titanate at low temperatures (450° C. or below) followed by plasma annealing in a high vacuum environment to achieve high-crystallinity barium titanate films with (001) or (111) crystal orientation, compatible with CMOS processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high temperature annealing (>600°C) is used to obtain high-quality ferroelectric layer, then crystallinity and ferroelectric properties are improved, but compatibility with back-end-of-line (BEOL) integration processes deteriorates
Solution Approach 1:
The patent changes the temperature parameter from conventional high temperature (>600°C) to low temperature (≤450°C) for the annealing process. This parameter change enables the formation of high-quality crystalline BTO films while maintaining compatibility with BEOL integration processes that cannot withstand high temperatures.
Solution Approach 2:
The patent replaces conventional thermal annealing with plasma annealing. This substitution allows crystallization to occur at lower temperatures by using plasma energy to activate the crystallization process without requiring high thermal energy, thus resolving the contradiction between achieving high crystallinity and maintaining process compatibility.
2Adaptability or versatility
If atomic layer deposition (ALD) is used to grow BTO films at low temperature, then compatibility with BEOL integration is improved, but crystallinity deteriorates (films remain amorphous)
Solution Approach 1:
The patent performs preliminary low-temperature ALD deposition to form the BTO film with good uniformity and stoichiometry control, then subsequently performs plasma annealing to induce crystallization. This two-step preliminary action sequence enables the film to achieve both low-temperature formation compatibility and high crystallinity.
Solution Approach 2:
The patent substitutes thermal annealing with plasma annealing to induce crystallization. The plasma provides energy for crystallization at lower temperatures than conventional thermal methods, enabling the transformation from amorphous to crystalline state while maintaining compatibility with low-temperature processing requirements.
3Manufacturing precision
If physical vapor deposition methods (MBE, PLD, magnetron sputtering) are used to grow crystalline BTO films, then crystallinity is improved, but process complexity and temperature requirements increase
Solution Approach 1:
The patent combines ALD deposition with plasma annealing in a single integrated process flow. The ALD process deposits the BTO film with precise stoichiometry control, and the subsequent plasma annealing step induces crystallization. This merging of deposition and crystallization steps simplifies the overall process compared to separate MBE or PLD operations.
Solution Approach 2:
The patent replaces complex physical vapor deposition methods (MBE, PLD, magnetron sputtering) with a simpler combination of ALD and plasma annealing. This substitution reduces process complexity while achieving the same goal of forming high-quality crystalline BTO films at lower temperatures.
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 enables the production of high-crystallinity barium titanate films at low temperatures, suitable for back-end-of-line integration, enhancing the compatibility with CMOS processes and expanding their application in ferroelectric elements and memory devices.
Implementation Method 1
growing them at a high temperature of 600-700° C. or above by physical vapor deposition, for example, molecular beam epitaxy (MBE)/pulsed laser deposition (PLD)/magnetron sputtering
Implementation Method 2
performing plasma annealing treatment on the barium titanate layer at a low temperature of 450° C. or below without breaking vacuum so as to crystallise the BTO layer
Implementation Method 3
Thermal annealing at a higher temperature after growth is also an effective method
Implementation Method 4
so as to crystallise the BTO layer and form a high-crystallinity barium titanate layer
Data Source
AI summary
The present invention provides a high-crystallinity barium titanate film structure, a method of preparation and an application thereof, and relates to the field of materials and devices. The method includes the steps of depositing, on a substrate, a barium titanate layer with a (001) or (111) crystal orientation by atomic layer deposition in a high vacuum environment and at a low temperature of 450° C. or below, wherein a Ba/Ti ratio in the barium titanate layer is 0.9-1.5; and performing plasma annealing treatment on the barium titanate layer at a low temperature of 450° C. or below without breaking vacuum to form a high-crystallinity barium titanate layer having the (001) or (111) crystal orientation. The film structure may further comprise top and bottom electrodes formed above and below the barium titanate layer. The present invention solves the problem that an existing method for obtaining a crystalline BTO film is not applicable to back-end of line (BEOL) integration processes.