Quantitative Analysis of the Incorporation Behaviors of Sr and Ti Atoms During the Atomic Layer Deposition of SrTiO3 Thin Films.

The atomic layer deposition (ALD) of multication oxide films is complicated because the deposition behaviors of the component oxides are not independent of one another. In this study, the Ti and Sr atom incorporation behaviors during the ALD of SrTiO3 films were quantitatively examined via the carefully designed ALD process sequences. H2O and O3 were adopted as the oxygen sources of the SrO subcycles, whereas only O3 was used for the TiO2 ALD subcycles. Apart from the general conjecture on the roles of the different types of oxygen sources, the oxygen source that was adopted for the subcycles of the other component oxide had almost complete control of the metal atom incorporation behaviors. This means that the first half-cycle of ALD played a dominant role in determining the metal incorporation rate, which revealed the critical role of the steric hindrance effect during the metal precursor injection for the ALD rate. O3 had almost doubled its reactivity toward the Ti and Sr precursors compared with H2O. Although these are the expected results from the common knowledge on ALD, the quantitative analysis of the incorporation behaviors of each metal atom provided insightful viewpoints for the ALD process of this technically important oxide material. Furthermore, the SrTiO3 films with a bulk dielectric constant as high as 236 were obtained by the Ru-SrTiO3-RuO2 capacitor structure.

Evaluating the top electrode material for achieving an equivalent oxide thickness smaller than 0.4 nm from an Al-doped TiO2 film.

The effects of Pt and RuO2 top electrodes on the electrical properties of capacitors with Al-doped TiO2 (ATO) films grown on the RuO2 bottom electrode by an atomic layer deposition method were examined. The rutile phase ATO films with high bulk dielectric constant (>80) were well-grown because of the local epitaxial relationship with the rutile structured RuO2 bottom electrode. However, the interface between top electrode and ATO was damaged during the sputtering process of the top electrode, resulting in the decrease in the dielectric constant. Postmetallization annealing at 400 °C was performed to mitigate the sputtering damage. During the postmetallization annealing, the ATO layer near the RuO2 top electrode/ATO interface was well-crystallized because of the structural compatibility between RuO2 and rutile ATO, while the ATO layer near the Pt top electrode/ATO interface still exhibited an amorphous-like structure. Despite the same thickness of the ATO films, therefore, the capacitors with RuO2 top electrodes showed higher capacitance compared to the capacitors with Pt top electrodes. Eventually, an extremely low equivalent oxide thickness of 0.37 nm with low enough leakage current density (<1 × 10(-7) A/cm(2) at 0.8 V) and physical thickness of 8.7 nm for the next-generation dynamic random access memory was achieved from ATO films with RuO2 top electrodes.

Mid to Long Term Follow-up Results of Reconstruction in Rheumatoid Arthritic Forefoot Deformities / 대한족부족관절학회지

PURPOSE: We assess the mid to long term follow up results of arthrodesis of the first metatarso-phalangeal (MTP) joint and resection arthroplasty of the lesser toes in rheumatoid arthritic forefoot deformity. MATERIALS AND METHODS: Between 1998 to 2001 year, 25 cases (18 patients) rheumatoid forefoot deformities were surgically corrected. Follow up period was 83 months (range, 63 to 90 months). The clinical outcome was evaluated using subjective satisfaction and AOFAS score. The radiological measurements were hallux valgus angle, first and second intermetatarsal angle, second metatarso-phalangeal angle (MTP-2nd angle). RESULTS: Subjective satisfaction was 76%. AOFAS score improved from 37 to 73. The hallux valgus angle improved from preoperative 39 degrees (27~64 degrees) to 14 degrees (4~34) at the last follow up. The intermetatarsal angle were preoperative 13 degrees (6~22 degrees) to 11 degrees (3~13 degrees) at the last follow up, The MTP-2nd angle were preoperative 24 degrees (9~47) to last follow up 15 degrees (2~39 degrees) respectively (p>0.05). Complication was intractable callus 10 cases, Interphalangeal arthritis 5 cases. CONCLUSION: Mid to long term outcomes rheumatoid forefoot reconstruction by first MTP arthrodesis and resection arthroplasty of lesser toes results a satisfaction and pain relief.