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Shun-ichiro OHMI Shin ISHIMATSU Yuske HORIUCHI Sohya KUDOH
We have investigated the in-situ N2-plasma nitridation for high-k HfN gate insulator formed by electron cyclotron resonance (ECR) plasma sputtering to improve the electrical characteristics. It was found that the increase of nitridation gas pressure for the deposited HfN1.1 gate insulator, such as 98 mPa, decreased both the hysteresis width in C-V characteristics and leakage current. Furthermore, the 2-step nitiridation process with the nitridation gas pressure of 26 mPa followed by the nitridation at 98 mPa realized the decrease of equivalent oxide thickness (EOT) to 0.9 nm with decreasing the hysteresis width and leakage current. The fabricated metal-insulator-semiconductor field-effect transistor (MISFET) with 2-step nitridation showed a steep subthreshold swing of 87 mV/dec.
Keisuke SHODA Masahiro MORIMOTO Shigeki NAKA Hiroyuki OKADA
Semitransparent organic solar cells were fabricated using lamination process. The devices were realized by using two independent substrates with transparent indium-tin-oxide electrode. One substrate was coated with poly(ethylenedioxy-thiophene)/poly(styrenesulfonate) layer and active layer of poly(3-hexylthiophene-2,5-diyl) (P3HT) and (6,6)-phenyl-C61 butyric acid methyl ester mixture. Another substrate was coated with ultra-thin polyethylenimine ethoxylated. The two substrates were laminated using hot press system. The device exhibited semitransparency and showed typical photovoltaic characteristics with open voltage of 0.59 V and short circuit current of 2.9 mA/cm2.