Deposition of Barium Strontium Titante (BaxSr1-xTiO3) Thin Films Doped Iron with Chemical Solution Deposition Method for Device Microwave Application.

SUMMARY

Deposition of Barium Strontium Titante (BaxSr1-xTiO3) Thin Films Doped Iron
with Chemical Solution Deposition Method for Device Microwave Application

By
Yofentina Iriani, Viska Inda Variani
Physics Department FMIPA, Sebelas Maret University

Many researchers interest to develop application of tunable microwave device as tunable
phase shifters, tunable filter, tunable oscillator, and resonator. Ferroelectric thin film is one of a
good candidate for these applications because it has low dielectric loss and high value of figure
of merit constant, K. The figure of merit constant depends on loss dielectric value and dielectric
constant value.
Barium Strontium Titanate (BaxSr1-xTiO3 or BST) is ferroelectric material which becomes
a candidate for tunable microwave device application. This material has element concentration
(mol), x which can be arranged to control Curie temperature, Tc of BST so operation temperature
of tunable microwave device can be controlled too.
This research goal is find out BaxSr1-xTiO3 formulation which is Fe doped so get sample
BaxSr1-xTiO3 which it has low dielectric loss and high value of figure of merit constant, K.
Variations of x value were done to observe phase changing. The CSD (Chemical Solution

Deposition) method in spin coating method is applied in this research which is planned running
for three years.
Parameter optimizations of BST fabrication were done in the first year of research.
Optimize rotate velocity of spin coating process 3000 rpm for 30 seconds. And then was
annealing in temperature 800 0Celcius for 30 minutes with heating rate 2 0Celcius/minutes. The
value of parameters will be used for BST fabrication in the second year of research.
Variations of x value for 0,5 until 0,9 on Pt/Si and Si substrates to observe electricity
changing of five samples were done in the second year of research. Samples fabrication of
BaxSr1-xTiO3 was succeed made since BST elements (Ba, Sr, and Ti) have been deposited on Pt/Si
substrate. Mol variation, x of BaxSr1-xTiO3 is not influence grain size. We get grain size 22 nm.
All samples is ferroelectric material because all of them can raise hysteresis curve. Ba 0,9Sr0,1TiO3

is sample with highest polarization. But Ba 0,7Sr0,3TiO3 is sample with highest dielectric constant
value.
Samples fabrication of BaxSr1-xTiO3 and BST which is Fe doped with mol variations were
succeed made since BST elements (Ba, Sr, and Ti) and Fe doping ion have been deposited on
Pt/Si substrate. Percentage mol variation of fe doping ion on Ba xSr1-xTiO3 influence molecule
vibration on BST structure. Addition Fe doping ion make grain size larger than without addition
Fe doping ion. Addition Fe doping ion 4 % make grain size the highest. Addition doping ion was
not made cracking on thin film surface. All samples are ferroelectric materials caused all of them

can raise hysteresis curve. BaSrFe0,04Ti0,96O3 is sample with highest polarization. Addition 4% Fe
doping ion can raise 15,6% remanent polarization. BaSrFe0,04Ti0,96O3 sample has highest dielectric
constant, 505.
Conclusion our research for three years is Ba0,7Sr0,3TiO3 which is doped 4 mol Fe doping on

Pt/Si substrate with velocity rate 3000 rpm for 30 seconds, annealing temperature 800 0C for 3
hours and heating rate 2 0C/minutes is the best quality material and recommend to apply as
tunable microwave device. This material has high polarization high capacitance and high
dielectric constant but low coercive field.