[22p-A307-1~17] CS.7 6.1 強誘電体薄膜、13.3 絶縁膜技術、13.5 デバイス／配線／集積化技術のコードシェア

[22p-A307-2] Field-Induced Polar-Axis Alignment for 3D High-Density Memory

〇李 卓¹、武 继璇¹、梅 潇然¹、黄 星宇¹、更屋 拓哉¹、平本 俊朗¹、髙橋 崇典²、上沼 睦典²、浦岡 行治²、小林 正治^1,3 (1.東大生産研、2.奈良先端、3.東大システムデザインセンター)

キーワード：FeFET、Hafnium Oxide

Ferroelectric FETs (FeFETs) have been attracting much attention for high speed and low power with the use of CMOS-compatible Fe-HfO₂. In addition, 3D vertical stack FeFETs can achieve more for high-density storage memory, with two additional challenges. 1) Typically, PVD cannot be used for conformal deposition in 3D structure. Thus ALD deposition is needed in a high-aspect ratio trench structure. 2) Fe-HfO₂ is usually poly-crystalline and does not assure out-of-plane polarization in as-grown layers. But it has to have out-of-plane polarization with respect to any type of surface in 3D structure. We consider how the polar-axis is aligned under the electric field. In this study, we theoretically investigate the polar-axis transition of FE-HfO₂ using the first-principle simulation, and experimentally fabricated HfZrO₂ films to observe and analyze grain crystal orientations. We confirmed polar-axis transition from in-plane to out-of-plane in Fe-HfO₂. This finding is useful in that Fe-HfO₂ can maximize the polarization for memory operation on any type of surface in 3D structure.