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標題: 鈦酸鈷高介電材料在非揮發性記憶體半球面型複晶矽浮動閘極上之應
CoTiO3 High-k Dielectric on HSG Floating Cell for Nonvolatile Memory
作者: 古惟銘
Gu, Wei Ming
關鍵字: CoTiO3;半球面型複晶矽;HSG;High-k Dielectric;高介電材料;鈦酸鈷
出版社: 電機工程學系

A novel high-k cobalt-titanium oxide (CoTiO3) was formed by low pressure chemical vapor deposition (LPCVD). It can be used for the interpoly dielectrics for nonvolatile memory, storage capacitor dielectric for DRAM and gate oxide for MOSFET applications. In this work, for the first time, the cobalt-titanium oxide (CoTiO3) was fabricated by directly oxidizing sputtered Co/Ti film on the differential process conditions poly-Si bottom electrodes with PVD-TiN as the top plate electrode. There are three various process to form poly-Si electrodes. The first type was hemi-spherical grained (HSG) with big grain size and high density (max AEF); The second type was an HSG formation with small grain size and high density. The last type was HSG formation with small grain size and low density (min AEF) was processed. The HSG poly-Si can enlargement floating gate surface area without increasing cell area. Therefore, we achieved low voltage operating flash memory cell with high coupling ratio. The increasing in the coupling ratio can reduce programming and erasing operation voltages.
In addition, the leakage current behavior in this high-k cobalt-titanium oxide (CoTiO3) capacitor structure was studied to determine the leakage current mechanisms. The effective dielectric constant with buffered layer for CoTiO3 dielectric can reach as high as 35. The capacitor on the HSG poly-Si with big grain size and high density has the largest surface area. It can enlargement floating gate surface area 2.2 times.
Appears in Collections:電機工程學系所

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