Polycrystalline SrBi2Ta2O9 thin films having a layered-perovskite structure were fabricated by a modified metalorganic solution deposition technique using room temperature processed alkoxidecarboxylate precursor solution. It was possible to obtain a complete perovskite phase at an annealing temperature of 650 °C and no pyrochlore phase was observed even up to 600 °C. In addition, the SrBi2Ta2O9 thin films annealed at 750 °C exhibited better structural, dielectric, and ferroelectric properties than those reported by previous techniques. The effects of postdeposition annealing on the structural, dielectric, and ferroelectric properties were analyzed. The electrical measurements were conducted on Pt/SrBi2Ta2O9/Pt capacitors. The typical measured small signal dielectric constant and dissipation factor at 100 kHz were 330 and 0.023 and the remanent polarization and the coercive field were 8.6 μC/cm2 and 23 kV/cm, respectively, for 0.25-μm-thick films annealed at 750 °C. The leakage current density was lower than 10−8 A/cm2 at an applied electric field of 150 kV/cm. The films showed good switching endurance under bipolar stressing at least up to 1010 switching cycles.
The crystallization behavior of antimony͑Sb͒-excess Ge 2 Sb 2+x Te 5 was examined. Sb-excess GST showed crystallization ͑T C ͒ and melting ͑T M ͒ temperatures of 205 and 550°C, respectively, slightly higher T C and lower T M values than stoichiometric Ge 2 Sb 2 Te 5 compounds. It also showed a substantially different crystallization behavior compared to the stoichiometric Ge 2 Sb 2 Te 5 composition. The resulting Sb-excess GeSbTe thin film showed a grain growth dominated crystallization behavior.
A large GaN-Schottky barrier diode (SBD) with a recessed dual anode metal is proposed to achieve improved the forward characteristics without a degradation of the reverse performances. Using optimized dry etch condition for a large device, the electrical characteristics of the device are demonstrated when applying the recessed dual anode metal and changing the recess depths. The device size and channel width are 4 mm 2 and 63 mm, respectively. The 16-nm recessed dual anode metal SBD has a turn-ON voltage of 0.34 V, a breakdown voltage of 802 V, and a reverse leakage current of 1.82 µA/mm at −15 V. The packaged SBD exhibits a forward current of 6.2 A at 2 V and a reverse recovery charge of 11.54 nC. Index Terms-AlGaN/GaN on Si, Schottky barrier diode (SBD), recess dual anode metal, low turn-on voltage.
I. INTRODUCTIONG ALLIUM nitride (GaN) power devices are drawing greater attention in high-power switching applications owing to their superior power density, efficiency, and switching speed [1]. To achieve high efficiency and a small size in a power-conversion system, a low turn-on voltage (V T ), low on-resistance (R on ) and low reverse recovery of the diode are very important [2]. Various technologies to improve the performance of an SBD have recently been studied. Researches to reduce on-resistance and to reduce surface leakage current, such as SiO 2 , SiN x , Al 2 O 3 dielectric film, have been investigated [3]. In addition, studies on recess etching in the anode region and recess depth control have been actively conducted owing to the capability of recessed SBDs to reduce the V T without an increase in the leakage current [4]-[6]. However, for large device fabrication, the dry etch conditions including a uniform etch profile, a reproducible etch rate, and a small amount of plasma damage are very difficult and Manuscript
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