Simulation and dielectric characterization of reactive dc magnetron cosputtered (Ta2O5)1−x(TiO2)x thin films

Abstract

Effects of substrate temperature on properties of pulsed dc reactively sputtered tantalum oxide films New capacitor material with high dielectric constant is needed for future integrated capacitor structures. Tantalum pentoxide (Ta 2 O 5 ) is considered as one of the most promising candidates. In this article, thin films of (Ta 2 O 5 ) 1Ϫx (TiO 2 ) x were grown utilizing reactive dc magnetron cosputtering of tantalum and titanium in an argon/oxygen atmosphere. By varying the input power at the targets, the composition of the thin film is easily controlled. The composition of the films was analyzed with elastic recoil detection analysis revealing the titanium oxide content ͑x ranging from 0 to 0.40͒. The presented results indicate that reactive sputter deposited tantalum pentoxide, with or without the addition of titanium, exhibits the properties required to meet the demands for future dielectric materials in integrated capacitors. The dielectric constant for metal-insulator-semiconductor structures is about 20 and the leakage current density is below 10 nA/cm 2 at 0.5 MV/cm, if the annealing temperature does not exceed 600°C. Annealing at 800°C leads to ϳ50% increase in dielectric constant with a cost of a severe increase in leakage current.

The importance of network structure in high-k dielectrics: LaAlO3, Pr2O3, and Ta2O5

“…At relatively low annealing temperatures ͑Ͼ700°C͒ orthorhombic 26 and hexagonal 26 crystalline phases have been stabilized. In the former case increased dielectric constants varying from 30 to 50 have been reported [27][28][29] whereas in the latter ͑hexagonal͒ the dielectric constant is reported between 55 and 64. 30 Note that the orthorhombic phase appears to be the most stable form.…”

Preparation of Dense Ta2O5‐Based Ceramics by a Coated Powder Method for Enhanced Dielectric Properties

“…[1][2][3][4] Cava et al 4 reported that K values for crystalline Ta 2 O 5 -based ceramics could be increased from 35 to 128 by the addition of 8% TiO 2 . Attempts to advance these findings have met with mixed success due to practical problems associated with complete densification, and no explanation has yet been offered for the observed enhancement of K. [4][5][6][7][8][9][10] In order to understand and make use of high-K Ta 2 O 5 -based materials, an investigation into the origins of dielectric phenomena is considered necessary; such a study requires dense and chemically homogeneous single-phase specimens.…”

Modeling of Reactive Sputtering—History and Development

“…In a large number of experiments, when changing Q 0 or the discharge current (power), the hysteresis effect was found. It was observed during the deposition of oxide films TiO 2 [25,26], Al 2 O 3 [27,28], Cd 2 SnO 4 [29,30], ZnO [31], Ta 2 O 5 [32], Ta 2 O 5 -TiO 2 [33] and nitrides AlN [34] and TiN [22,24,35]. The essence of the hysteresis resides in the following: there are two points of instability in the dependence of the X 2 reactive gas partial pressure on Q 0 at I = const (Figure 1a, curve 1).…”

“…A detailed analysis of the target state in the new model was supplemented by the equation of the steady state of the substrate (wall), which differed from the analogous equation in the Berg chemisorption model (33) in one detail:…”