Capacitor Crystallinity Inheritance via Polycrystalline Titanium Nitride
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Solution Overview
Problem
The challenge is to increase capacitor capacitance per unit area in semiconductor devices without decreasing the overall capacitance, as thinner capacitance dielectric films often result in lower dielectric constants due to parasitic capacitances and amorphous layers inheriting crystallinity from lower electrodes, leading to decreased capacitance.
Innovation Solution
A semiconductor device with a capacitor element where the lower electrode film comprises polycrystalline titanium nitride at least at the portion in contact with the capacitance dielectric film, ensuring the dielectric film inherits crystallinity and maintains high dielectric constant, thus increasing overall capacitance even when the thickness of the capacitance dielectric film is decreased.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the thickness of the capacitance dielectric film is decreased to increase capacitor capacitance per unit area, then the capacitor capacitance per unit area is improved, but the overall capacitor capacitance is lowered due to parasitic capacitance from amorphous layers
Solution Approach 1:
The invention changes the physical state parameter of the lower electrode film from amorphous to polycrystalline. This parameter change prevents the capacitance dielectric film from inheriting amorphous structure, thereby maintaining high dielectric constant and overall capacitance while achieving thinner film thickness for increased capacitance per unit area.
Solution Approach 2:
The invention applies local quality by ensuring that the lower electrode film has different crystallinity in different regions - specifically, the portion in contact with the capacitance dielectric film is made polycrystalline while other portions may remain amorphous. This localized polycrystalline structure prevents parasitic capacitance at the critical interface without requiring the entire lower electrode to be polycrystalline.
2Ease of manufacture
If the capacitance dielectric film is formed over an amorphous lower electrode film, then the manufacturing process is simplified, but the capacitance dielectric film becomes amorphous with low dielectric constant
Solution Approach 1:
The invention changes the physical state parameter of the lower electrode film from amorphous to polycrystalline. This parameter change prevents the capacitance dielectric film from inheriting amorphous structure, thereby maintaining high dielectric constant and overall capacitance while achieving thinner film thickness for increased capacitance per unit area.
Solution Approach 2:
The invention performs preliminary action by pre-forming the lower electrode film with polycrystalline structure before depositing the capacitance dielectric film. This preliminary polycrystalline structure serves as a template that prevents the capacitance dielectric film from becoming amorphous, ensuring high dielectric constant from the outset of the manufacturing process.
3Area of moving object
If a thin capacitance dielectric film is formed to increase capacitance density, then the capacitor capacitance per unit area is improved, but parasitic capacitance from oxide layers increases
Solution Approach 1:
The invention changes the physical state parameter of the lower electrode film from amorphous to polycrystalline. This parameter change prevents the capacitance dielectric film from inheriting amorphous structure, thereby maintaining high dielectric constant and overall capacitance while achieving thinner film thickness for increased capacitance per unit area.
Solution Approach 2:
The invention converts the potentially harmful effect of the lower electrode film interface into a beneficial one. By making the lower electrode film polycrystalline, the interface becomes a source of high dielectric constant rather than low dielectric constant, thereby converting what would be parasitic capacitance into useful capacitance.
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 effectively increases capacitor capacitance by maintaining high dielectric constant across the capacitance dielectric film, preventing the decrease in capacitance that occurs with amorphous lower layers, while allowing for thinner films without compromising capacitance.
Implementation Method 1
the capacitance dielectric film inherits the crystallinity of the polycrystalline titanium nitride
Data Source
AI summary
A method for manufacturing a semiconductor device includes a capacitor element in which a capacitance dielectric film is provided between an upper electrode film and a lower electrode film, includes forming the lower electrode film over the semiconductor substrate, forming the capacitance dielectric film over the lower electrode film, and forming the upper electrode film over the capacitance dielectric film, wherein, an entire surface layer of the lower electrode film is formed of a polycrystalline titanium nitride. At the portion of the capacitance dielectric film where directly contacting the entire surface layer of the lower electrode is formed of a polycrystalline metal oxide, and the polycrystalline metal oxide is formed by an ALD method and inherits a crystallinity of the polycrystalline titanium nitride.