• Journal of Magnetics
• /
• v.12 no.1
• /
• pp.21-26
• /
• 2007

Si-based electromagnetic noise suppressors on coplanar waveguide transmission lines incorporated with a $SiO_2$ dielectric layer and a nanogranular Co-Fe-Al-O magnetic thin film are reported. Unlike glass-based devices, large signal attenuation is observed even in the bare structure without coating the magnetic thin film. Much larger signal attenuation is achieved in fully integrated devices. The transmission scattering parameter ($S_{21}$) is as small as -90 dB at 20 GHz at the following device dimensions; the thicknesses of the $SiO_2$ and Co-Fe-Al-O thin films are 0.1 $\mu$m and 1 $\mu$m, respectively, the length of the transmission line is 15 mm, and the width of the magnetic thin film is 2000 $\mu$m. In all cases, the reflection scattering parameter ($S_{11}$) is below -10 dB over the whole frequency band. Additional distributed capacitance formed by the Cu transmission line/$SiO_2$/Si substrate is responsible for these characteristics. It is considered that the present noise suppressors based on the Si substrate are a first important step to the realization of MMIC noise suppressors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.58-61
• /
• 2001

Metal-insulator-semiconductor (MIS) C-V properties with high dielectric AIN thin films showed no hysteresis and good interface properties. The dielectric constant of the AIN film calculated from the capacitance at the accumulation region in the capacitance-voltage(C-V) characteristics was about 8. The C-V characteristics of MFIS capacitor showed a hysteresis loop due to the ferroelectric nature of the LiNbO$_3$ thin films. Typical dielectric constant value of LiNbO$_3$ film of MFIS device was about 23. The memory window width was about 1.2V at the gate voltage of $\pm$5 V ranges. Typical gate leakage current density of the MFIS structure was the order of 10$^{-9}$ A/cm$^2$ at the range of within $\pm$500 kV/cm. The ferroelectric capacitors showed no polarization degradation up to about 10$^{11}$ switching cycles when subjected to symmetric bipolar voltage pulse(peak-to-peak 8V, 50% duty cycle) in the 500kHz.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.1103-1106
• /
• 2006

We have presented a comprehensive study on threshold voltage $(V_{th})$ control of organic thin-film transistors (OTFTs) with dual-gate structure. The fabrication of dual-gate pentacene OTFTs using plasma-enhanced atomic layer deposited (PEALD) 150 nm thick $Al_2O_3$ as a bottom gate dielectric and 300 nm thick parylene or PEALD 200 nm thick $Al_2O_3$ as both a top gate dielectric and a passivation layer is reported. The $V_{th}$ of OTFT with 300 nm thick parylene as a top gate dielectric is changed from 4.7 V to 1.3 V and that with PEALD 200 nm thick $Al_2O_3$ as a top gate dielectric is changed from 1.95 V to -9.8 V when the voltage bias of top gate electrode is changed from -10 V to 10 V. The change of $V_{th}$ of OTFT with dual-gate structure has been successfully understood by an analysis of electrostatic potential.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.4
• /
• pp.274-280
• /
• 1998

Polycrystalline $Sr_2Nb_2O_7$ ceramics with very high Curie temperature were sintered using the powder derived by the chemical coprecipitation method (CCP). The phase evolution and grain-orientation of sintered samples were examined by XRD, while sintering behavior, dielectric properties and polarization were studied by SEM and ferroelectric tester. Extremely high degree of grain-orientation was observed along the (0k0) direction, which resulted in anisotropic dielectric properties of the sintered samples, with the dielectric constant values approaching those for single crystal. Thin film fabrication of $Sr_2Nb_2O_7$ in the pyroniobate family was also attempted on $SiO_2$/Si(100), Pt/$SiO_2$/Si(100), Pt/Ti/$SiO_2$/Si(100) and Pt/$ZrO_2/SiO_2/Si_2(100)$ substrates, using metalorganic decomposition (MOD) process. Neodecanoate precursor solution was prepared by mixing strontium neodecanoate with niobium neodecanoate synthesized from niobium ethoxide. It was found that $Sr_2Nb_2O_7$ single phase appeared in XRD patterns the samples annealed above $950^{\circ}C$. The effect of substrate type on film microstructure and dielectric properties was observed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.997-1000
• /
• 2001

Pb(Zr$\sub$0.52/Ti$\sub$0.48/)O$_3$(PZT) thin films have been prepared by rf-magnetron sputtering methods and investigated the structural and electrical properties. In order to investigate the effects of sputtering conditions, input power was controlled during deposition. Crystallization process and microstructure of PZT thin films were largely affected by input power. Highly crystallized PZT films with the perovskite structure were successfully obtained on Pt/Ti bottom electrode. The dielectric constants and polarization of PZT thin films were increased with increasing input power, and the coercive electric field was decreased with increasing input power . The dielectric constant of PZT thin films with input power 150 W was 966 at 1 kHz. we, authors, proposed that preferred orientation of PZT thin films were controlled by input power in sputtering methods.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.8
• /
• pp.671-676
• /
• 2009

The $Sr_{0.7}Bi_{2.3}Nb_2O_9$(SBN) thin films are deposited on Pt-coated electrode(Pt/Ti/$SiO_2$/Si) using RF sputtering method at various deposition conditions. We investigated the effect of deposition condition on the surface morphology and dielectric properties of SBN thin films. The optimum of the rougness showed about 4.33 nm in 70/30 of Ar/$O_2$ ratio. The crystallinity and rougness of SBN thin films were increased with the increase of rf power. Also, Deposition rate of SBN thin films was about 4.17 nm/min in 70 W of rf power. The capacitance of SBN thin films were increased with the increase of Ar/$O_2$ ratio, rf power and deposition temperature respectively.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.48 no.7
• /
• pp.514-520
• /
• 1999

Ferroelectric PZT(30/70)/PZT(70/30) heterolayered thin films were fabricated by spin-coating method on the $Pt/Ti/SiO_2Si$ substrate alternately using(30/70) and PZT(70/30) alkoxide solutions prepared by sol-coating method. The coating and heating procedure was repeated six times to form PZT heterolayered films, and thickness of the film obtained by one-times drying/sintering process was about 40-50 nm. All PZT heterolayered films, showed dense and homogeneous structure without the presence of rosette sturctrue. The relative dielectric constant, remanent polarization and leakage current density of PZT heterolayered films were superior to those of single composition PZT(30/70) and PZT(70/30) films, and those values for the PZT-6 film were 975, $21 \muC/cm^2\; and\; 8\times10^{-9}\; A/cm^2$, respectively. And the PZT-6 heterolayered film showed fairly good fatigue characteristics of remanent polarization and coercive field after application of $10^8$ switching cycles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.05c
• /
• pp.47-52
• /
• 2002

A processing method is developed for preparing sol-gel derived $Pb(Zr_{1-x}Ti_x)O_3$ (x=0.5) thin films on Pt-Ir($Pt_{80}Ir_{20}$)-alloy substrates. The as-deposited layer was dried on a plate in air at $70^{\circ}C$. And then it was baked at $1500^{\circ}C$, annealed at $450^{\circ}C$ and finally annealed for crystallization at various temperatures ranging from $580^{\circ}C$ to $700^{\circ}C$ for 1hour in a tube furnace. The thickness of the annealed film with three layers was $0.3{\mu}m$. Crystalline properties and surface morphology were examined using X-ray diffractometer (XRD). Electrical properties of the films such as dielectric constant, C-V, leakage current density were measured under different annealing temperature. The PZT thin film which was crystallized at $600^{\circ}C$ for 60minutes showed the best structural and electrical dielectric constant is 577. C-V measurement show that $700^{\circ}C$ sample has window memory volt of 2.5V and good capacitance for bias volts. Leakage current density of every sample show $10^{-8}A/cm^2$ r below and breakdown voltage(Vb) is that 25volts.

• Electrical & Electronic Materials
• /
• v.11 no.10
• /
• pp.66-71
• /
• 1998

Plasma polymerized hexamethyldisiloxane (PPHMDSO) thin films were produced using an electrode capacitively coupled apparatus. Fourier transform infrared spectroscopy analysis indicated that the thin film spectra are composed not only of the corresponding monomer bands but also of several new bands. Auger electron spectroscopy analysis indicated that the permeation depth of aluminum into the films is ca. 30nm when top electrode is deposited by evaporation aluminum. The increase of relative dielectric constant and decrease of dielectric loss tangent with the discharge power is originated from high cross-link of the films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.03b
• /
• pp.7-7
• /
• 2010

The SBN thin films were deposited at substrate temperature of 300[$^{\circ}C$] on Pt-coated electrode (Pt/Ti/$SiO_2$/Si(100)) using RF sputtering method. The grain and crystallinity of SBN thin films were increased with the increase of annealing temperature. The dielectric constant(150) of SBN thin film was obtained by annealing temperature above 750[$^{\circ}C$]. The frequency dependence of dielectric loss showed a value within 0.03 in frequency ranges of 1~1000[kHz].