One-transistor ferroelectric versatile memory: Strained-gate engineering for realizing energy-efficient switching and fast negative-capacitance operation
One-transistor ferroelectric versatile memory: Strained-gate engineering for realizing energy-efficient switching and fast negative-capacitance operation
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DOI：
10.1109/vlsit.2016.7573414
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发表时间：
2016-06
期刊：
影响因子：
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通讯作者：
Y. Chiu;Chun‐Hu Cheng;Chun-Yen Chang;Ying-Tsan Tang;Min-Cheng Chen
中科院分区：
文献类型：
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作者：
Y. Chiu;Chun‐Hu Cheng;Chun-Yen Chang;Ying-Tsan Tang;Min-Cheng Chen
在这项工作中，我们报告了一种采用应变栅极工程的铁电多功能存储器(FE-VM)。在相同的铁电厚度下，高应变情况下的记忆窗口提高了约47%，这与正交晶相结晶度的增加相一致。基于可靠的第一性原理计算(FPC)，我们阐明了栅应变在不增加介质厚度的情况下，加速了亚稳态单斜相向正交相的转变，从而大大增强了铁电极化。另一方面，正交FE-AFE相变在高栅极电场下实现负电容(NC)效应起着关键作用。这种采用铁电NC的1T应变栅极FE-VM在~40年的ID中实现了低于60 mVdec的亚阈值摆幅(SS)，以提供1~10 fA/μm Ioff和>；108 Ion/Ioff比，从而在1012循环耐久期间实现快速20 ns的P/E开关。
In this work, we report a ferroelectric versatile memory (FE-VM) with strained-gate engineering. The memory window of high strain case was improved by ~47% at the same ferroelectric thickness, which agrees with the increase of orthorhombic crystallinity. Based on a reliable first principle calculation (FPC), we clarify that the gate strain accelerates the phase transformation from metastable monoclinic to orthorhombic and thus largely enhances the ferroelectric polarization without increasing dielectric thickness. On the other hand, the orthorhombic FE-AFE phase transition plays a key role in realizing negative capacitance (NC) effect at high gate electric field. This 1T strained-gate FE-VM with ferroelectric NC achieves a sub-60-mVdec subthreshold swing (SS) over ~4 decade of ID to provide a 1~10 fA/μm Ioff and >108 Ion/Ioff ratio, which allows for a fast 20-ns P/E switching during 1012 cycling endurance.