Etching mechanisms of (Ba,Sr)TiO3 thin films in CF4/Ar inductively coupled plasma

Etching characteristics and plasma-induced damage of Ba0.65Sr0.35TiO3 thin films etched in CF4/Ar/O2 plasma

“…Moreover, the etch rate in a pure Ar plasma (5.83 nm/min) is about 1.45 times faster than that in a pure CF 4 plasma (4.01 nm/min). This result confirms that BST etching is dominated by Ar + bombardment and other ions assist reactions because of poor volatility of the etching by-products, such as BaF x , SrF y , and fluorocarbon polymers, while the contribution of chemical reactions between the BST film and reactive fluorine radicals should be secondary [15,16].…”

“…Note that the possible maximum etch rate is obtained when Ar/(CF 4 + Ar) ranges from 60% to 80% [15]. On this basis, CF 4 /Ar/O 2 gas mixtures are introduced in the reactive chamber.…”

“…This may result in the observed large difference of sputtering yield between Ba and Sr in the BST film during the physical sputtering process. It means that the removal of SrF y is most difficult, which can be expected from the melting point (T mp ) data: T mp (BaF 2 ) = 1368°C, T mp (SrF 2 ) = 1477°C, T mp (TiF 3 ) = 1200°C, T mp -(TiF 4 ) = 284°C [15]. Since the T mp (BaF 2 ) is lower than that of SrF 2 , one can expect that the Ba component can be removed more easily than that of Sr in fluorine-based compounds.…”

Aerosol deposition-based micropatterning of barium titanate via sulphur hexafluoride inductively coupled plasma etching

“…Second, in an Ar-rich atmosphere, the fraction of free surface increases rapidly, providing favourable conditions for both the physical sputtering etching and the chemical reaction. The increased efficiency of ion-stimulated desorption increases the rate of the chemical reaction in the SF 6 -rich plasma, decreasing the contribution of the plasma sputtering and shifting the maximum etching rate toward a lower Ar flow rate [16]. However, diluting the SF 6 with additional Ar decreases the BTO etching rate; the etching rate decreased to 57.5 nm/min and 56.2 nm/min at a respective Ar flow rate of 15 sccm and 20 sccm.…”

Etch Mechanism of Ba[sub 2]Ti[sub 9]O[sub 20] Dielectric Thin Film in Inductively Coupled Cl[sub 2]∕Ar Plasma

“…Most of existing data is related to ͑BaSr͒TiO 3 ͑BST͒ in CF 4 /Ar, Cl 2 /Ar, and Cl 2 /CF 4 /Ar gas chemistries. [6][7][8][9][10] The problem is that, in spite of quite similar structures for BTO and BST, the basic properties determining the plasma-assisted etch mechanism are not close. First, the Ba:Ti ratios in BST ͑Ba:Ti = 1:1͒ and BTO ͑Ba:Ti = 2:9͒ are very different.…”