• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2011년도 춘계학술발표대회
• /
• pp.28.2-28.2
• /
• 2011

Resistance random access memory (ReRAM) is a promising candidate for next-generation nonvolatile memory because of its advantageous qualities such as simple structure, superior scalability, fast switching speed, low-power operation, and nondestructive readout. We investigated the resistive switching behavior of tantalum oxide that has been widely used in dynamic random access memories (DRAM) in the present semiconductor industry. As a result, it possesses full compatibility with the entrenched complementary metal-oxide-semiconductor processes. According to previous studies, TiN is a good oxygen reservoir. The TiN top electrode possesses the specific properties to control and modulate oxygen ion reproductively, which results in excellent resistive switching characteristics. This study presents fully room temperature fabricated the TiN/$TaO_x$/Pt devices and their electrical properties for nonvolatile memory application. In addition, we investigated the TiN electrode dependence of the electrical properties in $TaO_x$ memory devices. The devices exhibited a low operation voltage of 0.6 V as well as good endurance up to $10^5$ cycles. Moreover, the benefits of high devise yield multilevel storage possibility make them promising in the next generation nonvolatile memory applications.

• 센서학회지
• /
• 제18권5호
• /
• pp.343-348
• /
• 2009

$NiO{\cdot}(Co_{0.25}Mn_{0.75})_2O_3$(Mn-Ni-Co) and $Ba_{0.5}Sr_{0.5}TiO_3$(BST) thick films were screen printed on Pt patterned alumina substrate to investigate the effects of sintering temperature on humidity and temperature sensing properties of ceramic sensors. A raise in sintering temperature increased resistance and B constant of the Mn-Ni-Co temperature sensor. This may have derived from the synergic effects of the reduction in charge carriers caused by the substitution of Co for Mn as well as the formation of microcracks from the difference in thermal expansion coefficients. Dependence of resistance on humidity of the Mn-Ni-Co temperature sensor, however, was not found. BST films sintered at temperatures in the range of $1100^{\circ}C$ to $1150^{\circ}C$ showed excellent humidity sensing properties. The BST humidity sensor was faster in its response than the Mn-Ni-Co temperature sensor. The humidity sensor, however, proved to be unstable under various temperatures, suggesting a need for a temperature stabilizing device. In contrast, the Mn-Ni-Co temperature sensor was stable under humid conditions.

• 한국재료학회지
• /
• 제34권3호
• /
• pp.152-162
• /
• 2024

In this study, we introduce a novel TiN/Ag embedded TiO₂/FTO resistive random-access memory (RRAM) device. This distinctive device was fabricated using an environmentally sustainable, solution-based thin film manufacturing process. Utilizing the peroxo titanium complex (PTC) method, we successfully incorporated Ag precursors into the device architecture, markedly enhancing its performance. This innovative approach effectively mitigates the random filament formation typically observed in RRAM devices, and leverages the seed effect to guide filament growth. As a result, the device demonstrates switching behavior at substantially reduced voltage and current levels, heralding a new era of low-power RRAM operation. The changes occurring within the insulator depending on Ag contents were confirmed by X-ray photoelectron spectroscopy (XPS) analysis. Additionally, we confirmed the correlation between Ag and oxygen vacancies (V_o). The current-voltage (I-V) curves obtained suggest that as the Ag content increases there is a change in the operating mechanism, from the space charge limited conduction (SCLC) model to ionic conduction mechanism. We propose a new filament model based on changes in filament configuration and the change in conduction mechanisms. Further, we propose a novel filament model that encapsulates this shift in conduction behavior. This model illustrates how introducing Ag alters the filament configuration within the device, leading to a more efficient and controlled resistive switching process.

• 한국진공학회지
• /
• 제5권4호
• /
• pp.333-340
• /
• 1996

Cu 확산방지막으로서의 Tin의 특성을 면저항 특정, X선 회절 분석, SEM, AES, capacitance-voltage(C-V) 측정에 의하여 평가하고, Cu의 확산을 민감하게 알아내는 정도를 특성 평가 방법간에 비교하였다. 여러 가지 증착방법에 의하여 Cu/TiN/Ti/SiO2/Si 구조의 다층 박막시편을 제작하였으며, 이 시편을 10% H2/90% Ar분위기, 열처리 온도 500~$800{\circ}C$ 범위에서 2시간 동안 열처리하였다. TiN의 Cu 확산방지 효과가 소멸된 경우 Cu 박막 표면에서 불규칙한 모양의 spot을 관찰할 수 있었으며 outdiffusion된 Si를 검출할 수 있었다. MOS capacitor의 C-V 특성은 열처리 온도에 따라 급격하게 변화하였다. C-V 측정에서 inversion capacitance는 열처리 온도 500~$700^{\circ}C$범위에서 열처리 온도가 높아질수록 감소하다가 $800^{\circ}C$에서 크게 증가하였으며, 이러한 특성의 변화는 TiN을 통해서 $SiO_2$와 Si내로 확산된 Cu에 의하여 발생되는 것으로 생각된다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
• /
• pp.1881-1883
• /
• 2005

In this study, PZT thin films were fabricated using sol-gel Processing onto $Si/SiO_2/Ti/Pt$ substrates. PZT sol with different Zr/Ti ratio(20/80, 30/70, 40/60, 52/48) were prepared, respectively. The films were fabricated by using the spin-coating method on substrates. The films were heat treated at $450^{\circ}C$, $650^{\circ}C$ by rapid thermal annealing(RTA). The preferred orientation of the PZT thin films were observed by X-ray diffraction(XRD), and Scanning electron microscopy(SEM). All of the resulting PZT thin films were crystallized with perovskite phase. The fine crystallinity of the films were fabricated. Also, we found that the ferroelectric properties from the dielectric constant of the PZT thin films were over 600 degrees, P-E hysteresis constant. And the leakage current densities of films were lower than $10^{-8}\;A/cm^2$. It is concluded that the PZT thin films by sol-gel process to be convinced of application for ferroelectric memory device.

• 한국진공학회지
• /
• 제18권1호
• /
• pp.60-65
• /
• 2009

본 연구에서는 분광타원분석법을 이용하여 최근 주목 받고 있는 microwave dielectric materials 인 $BaSm_2Ti_4O_{12}$ 박막의 광 특성을 $0.92{\sim}8.6\;eV$ 에너지 영역에서 분석하였다. 광역 에너지영역에서 측정이 가능한 Vacuum Ultra Violet spectroscopic ellipsometer를 사용하여 시료의 광 스펙트럼을 측정 하였으며, 측정된 스펙트럼으로부터 $BaSm_2Ti_4O_{12}$ 박막의 광 특성을 얻기 위하여 Tauc-Lorentz 분산 함수를 이용하였고, 고 에너지 영역대의 새로운 피크구조 (structure) 를 최초로 발견하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1994년도 하계학술대회 논문집 C
• /
• pp.1472-1474
• /
• 1994

In this paper, $TiO_2-V_2O_5$ thin films are fabricated by Sol-Gel method and their humidity-sensing characteristics have been investigated. The microstructure of specimen is porous. The humidity-sensing characteristics of thin films are good according to increasing heat treatment temperature and decreasing measurement frequency.

• 한국세라믹학회지
• /
• 제33권10호
• /
• pp.1101-1108
• /
• 1996

No-doped PZT thin films have been fabricated on Pt/Ti/SiO2/Si substrate using Sol-Gel technique. A fast annealing metho (three times of intermediate and final annealing) was used for the preparation of multi-coated 1800$\AA$ thick Nb-doped PZT thin films. As Nb doping percent was increased leakage current was lowered approximately 2 order but dielectic properties were degraded due to the appearance of pyrochlore phase and domain pinning. Futhermore the increase of the final annealing temperature up to 74$0^{\circ}C$lowered the pyrochlore phase content resulting in enhancing the dielectric properties of the Nb doped films. The 3%-Nb doped PZT thin films with 5% excess Pb showed a capacitance density of 24.04 fF/${\mu}{\textrm}{m}$2 a dielectric loss of 0.13 a switchable polarization of 15.84 $\mu$C/cm2 and a coercive field of 32.7 kV/cm respectively. The leakage current density of the film was as low as 1.47$\times$10-7 A/cm2 at the applied voltage of 1.5 V.

• 한국안광학회지
• /
• 제3권1호
• /
• pp.217-222
• /
• 1998

$SiO_2-TiO_2-AgO$ 코팅박막을 졸-겔법으로 현미경용 슬라이드 유리판과 씰리콘 기판에 제조하였다. 이 박막의 열처리온도는 $500^{\circ}C$가 적절하였으며 5회 반복코팅한 박막의 두께는 310nm였다. AgO가 10mol% 첨가된 박막의 표면은 균일한 구조를 보였으나 첨가량이 많아질수록 박막의 표면에 pin hole과 AgO의 석출에 기인한 cluster를 보였다. 열처리온도의 증가에 따라 IR흡수의 정도가 점차 감소하였고, AgO 첨가량의 증가에 따라 반사율은 점차 감소하였으며 색상은 light yellow에서 무채색 쪽으로 점차 전이하였다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
• /
• pp.367-370
• /
• 2004

We fabricated PLT(5) thin film on $Pt/TiO_x/SiO_2/Si$ substrate by using sol-gel method and investigated leakage current, switching and retention properties. The leakage current density of PLT(5) thin film was $3.56{\times}10^{-7}A/cm^2$ at 4V. In the examination of switching properties, pulse voltage and load resistance were $2V{\~}5V$ and $50{\Omega}{\~}3.3k{\Omega}$, respectively. Switching time had a tendency to decrease from 520ns to 140ns with the increase of pulse voltage, and also the time was increased from 140ns to $13.7{\mu}s$ with the increase of load resistance. The activation energy obtained from the relation of applied pulse voltage and switching time was about 143kV/cm. The error of switched charge density between hysteresis loop and experiment of polarization switching was about $10\%$. Also, polarization in retention was decreased as much as about $8\%$ after $10^5$s.