1999) Intrinsic stress dependence of Pt hillock formation and its related electrical properties of SBT capacitor, The P f l i electrode stacks were deposited on the SiOxiSi substrate by DC magnetron sputtering. The Pt layers were deposited at various temperature of RT-500"C. These electrode stacks were annealed at 6 5 0 T for 30min in O2 ambient. A lot of high hillocks were observed on the Pt surface deposited at low temperatures (RT-300°C) after the anneal process. But the hillocks were decreased in both number and height with increasing the deposition temperature of the Pt layer. We found in both SEM inspection and stress measurement that the deposition temperature dependence of the Pt hillock formation could be explained by the difference in the intrinsic stress generated during deposition process. We also demonstrated the effect of Pt hillocks on electrical properties of SBT capacitor. The 2Pr values of the SBT capacitors were about 13p C/cm2 regardless of the Pt deposition temperatures. But the short probabilities were decreased with the increase of the Pt deposition temperatures. This result is well consistent with the trend of Pt hillock formation.
SrBi2Ta2O9 (SBT) film was crystallized to form fine grains and a smooth surface by rapid thermal annealing (RTA), but form large grains and a rough surface by main furnace annealing. The sequence of furnace annealing was changed to improve the morphology of the Pt/SBT interface and the leakage property of a Pt/SBT/Pt capacitor. For the conventional sequence of furnace annealing before top electrode deposition, the capacitor showed a good switching polarization (P*-P∧) of 17 µC/cm2 but a high short fail rate of 56% due to the rough Pt/SBT interface. However, using the new sequence of furnace annealing after top electrode deposition on RTA-treated SBT film, a very smooth Pt/SBT interface and a resultant low short fail rate of 7% was obtained, but the value of P*-P∧ was decreased to 14 µC/cm2 due to a restrained grain growth of the SBT film under Pt top electrode.
Uterine arteriovenous malformation (AVM) is a vascular hamartoma of the myometrium that mostly results from uterine tissue damage. Herein, we report a case of uterine AVM managed successfully by hysteroscopy. The patient had an induced abortion and subsequent persistent vaginal spotting and irregular active vaginal bleeding. Ultrasonography showed a 3.5 cm × 2.9 cm heterogeneous lesion in the endometrial cavity with increased vascularity. Symptoms were monitored without uterine artery embolization to avoid complications that may affect a future pregnancy. However, 10 days later, she presented with active vaginal bleeding. Hysteroscopic endometrial mass excision was performed. Her postoperative hemoglobin level and vital signs were stable. Biopsy of the excised mass revealed AVM. Her postoperative vaginal bleeding decreased significantly, and outpatient ultrasonography 1 month later showed no abnormal findings. This case confirms the feasibility and safety of hysteroscopic management of uterine AVMs. The hysteroscopic technique should be prioritized for managing uterine AVMs.
Bi 4Àx La x Ti 3 O 12 (BLT) ferroelectric thin films were prepared on a Pt/TiO x /SiO 2 /Si substrate using metalorganic decomposition (MOD) method, and their electrical properties were evaluated with thickness, composition and crystallization annealing temperature. Irrespective of the preparation conditions, BLT films were c-axis oriented, and had a dense surface morphology without pore to produce smooth Pt/BLT/Pt interfaces of capacitor. The film thickness was controlled as 90 nm to obtain a low coercive voltage (2V c ) without the problem of capacitor short-fail. The proper composition of Bi 3:35 La 0:85 Ti 3 O 12 was selected for the largest switching polarization (P Ã À P^), good fatigue endurance and a low leakage current density (J L ). After crystallization annealing at 700 C, the optimized film of 90 nm Bi 3:35 La 0:85 Ti 3 O 12 showed the good electrical properties, such as 2V c of 2.0 V, P Ã À P^of 13 C/cm 2 , J L of 1 Â 10 À6 A/cm 2 at a applied voltage of 3 V and no polarization loss up to 1 Â 10 11 fatigue cycles, for ferroelectric random access memory (FeRAM) application.
Ferroelectric SrBi2(Ta,Nb)2O9 (SBTN) thin films were deposited on Pt (200 nm)/TiOx(40 nm)/SiO2 (100 nm)/Si substrates by metal‐organic decomposition. The effects of bombardment from accelerated argon and oxygen ions on the properties of SBTN thin films were investigated. It was found that the argon ion bombardment could decrease the crystallization temperature owing to the increase of internal energy of the films. Also, the oxygen vacancies at the interface between the SBTN film and platinum bottom electrode or at grain boundaries in the film were passivated through the oxygen ion treatment, resulting in the improved electrical properties. By optimizing the process parameters and using bombardment of accelerated argon and oxygen ions, SBTN films with good ferroelectric and electrical properties could be obtained, at a temperature as low as 650°C.
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