• Journal of the Korean Ceramic Society
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• v.34 no.10
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• pp.1060-1066
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• 1997

In this paper, the effects of La addition of PLZT thin film prepared by sol-gel method on the capacitor characteristics are investigated for gigabit generation DRAM applications. The addition of La on the PLZT capacitor results in a trade-off between charge storage density(Qc') and leakage current density(Jl). As La content increases, Qc' and permeability(εr) at 0V are reduced while Jl is significantly decreased. It is demonstrated that 5% La doping of PZT can substantially reduce Jl and also improve resistance to fatigue while incurring only minimal degradation of Qc'. Very low leakage current density (5×10-7 A/㎠ even at 125℃) and high charge storage density (100fC/㎛2) under VDD/2=1V conditions are achieved using 5% La doped PZT thin films for gigabit DRAM capacitor dielectrics. In addition, the fatigue and TDDB measurements indicate good reliability of the PLZT capacitors.

• Journal of the Korean Vacuum Society
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• v.18 no.1
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• pp.30-36
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• 2009

The effects of $HfO_2$ film thickness on electrical, optical, and structural properties were investigated. We fabricated ITO/$HfO_2$/ITO metal-insulator- metal (MIM) capacitor using transparent conducting oxide. When $HfO_2$ film thickness increase from 50 nm to 300 nm, dielectric constant of $HfO_2$ was decreased from 20.87 to 9.72. The transparent capacitor shows an overall high performance, such as a dielectric constant about 21 by measuring the ITO/$HfO_2$/ITO capacitor structures and a low leakage current of $2.75{\times}10^{-12}\;A/cm^2$ at +5 V. Transmittance above 80% was observed in visible region.

• Korean Journal of Materials Research
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• v.12 no.1
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• pp.75-81
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• 2002

The ferroelectric properties of Pb(Zr,Ti)O$_3$[PZT] films degrade when the films with Pt top electrodes are annealed in hydrogen containing environment. This is due to the reduction activity of atomic hydrogen that is generated by the catalytic activity of the Pt top electrode. At the initial stage of hydrogen annealing, oxygen vacancies are formed by the reduction activity of hydrogen mainly at the vicinity of top Pt/PZT interface, resulting in a shift of P-E (polarization-electric field) hysteresis curve toward the negative electric field direction. As the hydrogen annealing time increases, oxygen vacancies are formed inside the PZT film by the inward diffusion of hydrogen ions, as a result, the polarization degrades significantly and the degree of P-E curve shift decreases gradually. The direction and the magnitude of the remnant polarization in the PZT film affect the motion of hydrogen ions which determines the degradation of polarization characteristics and the shift in the P-E hysteresis curve of the PZT capacitor during hydrogen annealing. When the remnant polarization is formed in the PZT film by applying a pre-poling voltage prior to hydrogen annealing, the direction of the P-E curve shift induced by hydrogen annealing is opposite to the polarity of the pre-poling voltage. The hydrogen-induced degradation behavior of the PZT capacitor is also affected by the internal field that has been generated in the PZT film by the charges located at the top interface prior to hydrogen annealing.

• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.32-37
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• 2019

Titanium dioxide ($TiO_2$) is a promising dielectric material in the semiconductor industry for its high dielectric constant. However, for utilization on Si substrate, $TiO_2$ film meets with a difficulty due to the large leakage currents caused by its small conduction band energy offset from Si substrate. In this study, we propose an in-situ plasma oxidation process in plasma-enhanced atomic layer deposition (PE-ALD) system to form an oxide barrier layer which can reduce the leakage currents from Si substrate to $TiO_2$ film. $TiO_2$ film depositions were followed by the plasma oxidation process using tetrakis(dimethylamino)titanium (TDMAT) as a Ti precursor. In our result, $SiO_2$ layer was successfully introduced by the plasma oxidation process and was used as a barrier layer between the Si substrate and $TiO_2$ film. Metal-oxide-semiconductor ($TiN/TiO_2/P-type$ Si substrate) capacitor with plasma oxidation barrier layer showed improved C-V and I-V characteristics compared to that without the plasma oxidation barrier layer.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.8
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• pp.78-85
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• 1995

We fabricated the Pb$_{1-0.28{\alpha}}La_{0.28}TiO_{3}$ (PLT(28)) thin film successfully by using the sol-gel method and characterized it to evaluate its potential for being utilized as the capacitor dielectrics of ULSI DRAMs. In our sol-gel process, the acetates were used as the starting materials. Through the TGA-DTA analysis, we established the excellent fabrication conditions of the sol-gel method for the PLT(28) thin film. We obtained the dense and crack-free PLT(28) thin film of 100% perovskite phase by drying at 350$^{\circ}C$ after each coating and final annealing at 650$^{\circ}C$. Its electrical properties were measured from the planar capacitors fabricated on the Pt/Ti/SiO$_{2}$/Si substrate. By the P-E hysteresis measurement, its paraelectric phase was identified and its dielectric constant and leakage current density were measured as 936 and 1.1${\mu}A/cm^{2}$, respectively. Those electrical values indicate that the PLT(28) thin film is the most successful candidate for the capacitor dielectrics of ULSI DRAMs at the present.

• Korean Journal of Materials Research
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• v.3 no.1
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• pp.19-27
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• 1993

Abstract The PZT thin film was deposited by usin. RF magnetron sputtering with PZT(52/48) target. The formation of perovskite structure PZT thin film started at 55$0^{\circ}C$ on Si substrate. The AES results showed an oxide layer formed at the between Si and PZT film during the annealing. And, Ti$O_2$ layer appeared at the between TiN and PZT film for the annealing. But, the perovskite phase PZT film was formed after the annealing on the Si$O_2$/Si substarte. The ratio in PZT film was constant across the asdeposited PZT film, but, Pb have diffused into the Si substrate and Si have out-diffused into PZT layer during the post annealing at 75$0^{\circ}C$. The dielectric constants of PZT film indicated about 1300( thickness: 1500$\AA$, at 10KHz) but, the cracks were appeared to surface for annealing.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.3 s.94
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• pp.253-259
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• 2005

In this paper, BaSrTiO$_{3}$(BST) thin film tunable interdigital capacitor using low cost silicon substrate instead of expensive single-crystalline substrate is presented. The tunable capacitor in which BST thin film is deposited by PLD has operation frequency and applied bias up to 4 GHz and 50 V, respectively. The maximum tunability in capacitance is found to be 30$\%$, for an applied field of 5 kV/cm at a bias of 50 V. Therefore, it has been shown that the BST microwave tunable capacitor can be integrated onto Si substrate.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.4
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• pp.1-6
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• 2005

Recently embedded passive technology which fabricate passive elements such as resistors and capacitors at the inner layer of PCB(Printed Circuit Board) is used to make high performance IT products. However, embedded capacitor has limit in full range circuit applications because of the low capacitance density. In this paper, a new embedded capacitor which has wrinkled electrodes and dielectric layer was proposed to overcome the limits. FEM(Finite Elements Method) technique was used to evaluate capacitance density of the wrinkled type embedded capacitor. Capacitance density of the wrinkled type embedded capacitor is larger than that of conventional planar type embedded capacitor by about 25.6%$\sim$39.6%. In case of thin film type embedded capacitor, proposed wrinkled structure has more enhanced effect on the capacitance density.

• Proceedings of the Materials Research Society of Korea Conference
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• 1993.11a
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• pp.108-109
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• 1993

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.73-74
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• 1998