A study of barium strontium titanate thin films for use in bypass capacitors

Abstract

Physical and electrical characterization techniques have been applied to the problem of developing a lower temperature process for spin-on Ba 0.7 Sr 0.3 TiO 3 thin films and capacitors compatible with on-chip aluminum metallization. The films were prepared by spin-coating from carboxylate precursors and were processed at temperatures between 650 ± C and 450 ± C. Capacitors annealed at higher temperatures have a dielectric constant (k) of 382, a C͞A of 20 fF͞mm 2 , and a leakage current density of 2 3 10 27 A͞cm 2 at 3.3 V. Those processed at 450 ± C show occasionally promising but inconsistent results, correlated using TEM images with locally variable crystallization into the perovskite phase. The kinetics of the spin-on solution chemical decomposition and crystallization has been investigated through the use of x-ray diffraction (XRD), thermogravimetric analysis (TGA), and Raman spectroscopy.

Modified Spin Coating Method for Coating and Fabricating Ferroelectric Thin Films as Sensors and Solar Cells

“…Ferroelectric thin films such as barium strontium titanate, lithium tantalate, and lithium niobate can be manufactured by using CSD method and then performed by the spin coating process [1]. CSD method is one of the methods to create/develop thin films [2][3][4][5][6][7][8][9][10][11][12], which has advantages including the ability to control the film stoichiometry with good quality, easy procedure, require relatively low cost, and generate a good crystalline phase [13][14][15]. In addition, thin films can also be fabricated by other methods such as metal organic chemical vapor deposition (MOCVD) [16][17][18], chemical vapor deposition [19], sol-gel [20][21][22][23], atomic layer deposition (ALD) [24], metal organic decomposition (MOD) [25], pulsed laser ablation deposition (PLAD) [26,27], and RF sputtering [2,21,28].…”

Fabrication and electrical properties of sol-gel-derived Ba 0.8 Sr 0.2 TiO 3 ferroelectric films from a 0.05-M spin-on solution

“…This is in contrast to Pb(Ti, Zr)O 3 films, which can easily be grown by the solgel method into a columnar or epitaxial structure, because of heterogeneous nucleation from a nanocrystalline pyrochlore phase into the perovskite phase at the substrate [13]. (iii) The tetragonality (c/a) of BST films decreases with the increasing of strontium content [7], and a small c/a value may not be sufficient to create charge separation and spontaneous polarization in the films [14], so the fabrication of BST ferroelectric film is more difficult than that of BaTiO 3 . A sol-gelderived ferroelectric BaTiO 3 film on a Pt/Ti/SiO 2 /Si substrate that showed a good ferroelectric hysteresis loop has recently been reported by Sharma et al [15].…”

“…Compared to other deposition methods, the sol-gel process offers some advantages, such as homogeneity, stoichiometry control, and the ability to coat large and complex area substrates. However, the sol-gel-derived BST films always fail to display pronounced ferroelectric hysteresis loops [6][7][8][9][10]. This makes the sol-gel-derived BST thin films unsuitable for uncooled infrared detector applications.…”

Surface Roughness and Grain Size Characterization of Annealing Temperature Effect For Growth Gallium and Tantalum Doped Ba_0.5 Sr_0.5TiO₃Thin Film

“…Thin BaTiO 3 (BT) and Ba 0.5 Sr 0.5 TiO 3 (BST) is a well known dielectric material and has been attractive for the applications such as capacitors and high density dynamic random access memory (DRAM) due to its high dielectric constant and high capacity of charge storage [1,2] and solar cell [3].…”

“…BT and BST films can be formed by various methods, such as chemical solution deposition (CSD) [1,2,4], metal organic chemical vapor deposition (MOCVD) [5][6][7], rf sputtering [8][9][10][11][12][13] and Pulsed Laser Ablation Deposition (PLAD) [14]. CSD Method is of particular interest because of its good control of stoichiometry, ease of fabrication and low temperature synthesis.…”