Study of damage reduction of (Ba0.6,Sr0.4)TiO3 thin films etched in Ar/CF4 plasmas

Abstract

Articles you may be interested inEffect of oxygen gas and annealing treatment for magnetically enhanced reactive ion etched ( Ba 0.65 , Sr 0.35 ) Ti O 3 thin films A barium strontium titannate ͑BST͒ thin films were etched in CF 4 /Ar using inductively coupled plasma. The high etch rate obtained at a CF 4 ͑20%͒/Ar͑80%͒ and the etch rate in pure argon was twice as high as that in pure CF 4 . This indicated that BST etching is a sputter-dominated process. It is impossible to avoid plasma-induced damage by energetic particles in the plasma and the contamination of nonvolatile etch products. The plasma damage was evaluated in terms of leakage current density, residues on the etched sample, and the change in roughness. After the BST thin films were exposed in the plasma, the leakage current density and roughness increased. In addition, there are appeared a nonvolatile etch products and the x-ray diffraction ͑XRD͒ ͑110͒ and ͑111͒ intensities are decreased and broaden. After annealing at 600°C in O 2 ambient for 10 min, the leakage current density, roughness, and nonvolatile etch products were reduced and the XRD ͑110͒ and ͑111͒ intensities increased. From these results, the attribution of the recovery of plasma induced damage by annealing process is owing to the desorption of metal fluorides at high temperature.

Etching mechanism of barium strontium titanate (BST) thin films in CHF3/Ar plasma

“…Thus, identifying by-product compositions is important for optimizing etching processes. There are several reported studies on the etching of BST thin films using chlorine and fluorine-based plasma chemistry [9][10][11][12][13][14][15][16][17]. There are also several reports investigating the properties of CF 4 /Ar plasmas both experimentally and theoretically.…”