Quantum Capacitance Limited Vertical Scaling of Graphene Field-Effect Transistor
Quantum Capacitance Limited Vertical Scaling of Graphene Field-Effect Transistor
复制标题
量子电容限制石墨烯场效应晶体管的垂直缩放
DOI：
10.1021/nn200026e
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发表时间：
2011-03-01
期刊：
影响因子：
17.1
通讯作者：
Peng, Lian-Mao
中科院分区：
文献类型：
--
作者：
Xu, Huilong;Zhang, Zhiyong;Peng, Lian-Mao
直接在石墨烯上生长高质量的Y2O3介电层，用于制作顶栅石墨烯场效应晶体管（FET），介电层的厚度不断减薄至39 nm，等效氧化物厚度（EOT）为15 nm，具有优异的绝缘性。通过测量两个具有不同栅极的石墨烯FET的CV特性；氧化物厚度、氧化物电容和量子电容直接从实验CV数据中检索，无需引入任何额外的拟合过程和参数，得到石墨烯上Y2O3的相对介电常数kappa = 10和约2.28-mu F/cm(2)的氧化物电容。发现对于相当大的栅极电压范围，该氧化物电容是相当的；有时甚至大于石墨烯的量子电容。由于总栅极电容由氧化物和量子电容中较小的一个决定，因此我们的结果表明，通过进一步垂直缩小栅极氧化物并不能获得太大的进一步改进，这表明Y2O3可能是石墨烯的最终介电材料。还显示了； EOT为1.5nm的Y2O3栅介质层也可以满足石墨烯FET栅长的最终横向缩放要求，可有效用于控制栅长小至1nm的石墨烯FET。
A high-quality Y2O3 dielectric layer has been grown directly on graphene and used to fabricated top-gate graphene field-effect transistors (FETs), and the thickness of the dielectric layer has been reduced continuously down to 39 nm with an equivalent oxide thickness (EOT) of 15 nm and excellent insulativity. By measuring CV characteristics of two graphene FETs with different gate; oxide thicknesses the oxide capacitance and quantum capacitance are retrieved directly from the experimental CV data without Introducing any additional fitting process and parameters, yielding a relative dielectric constant of kappa = 10 for Y2O3 on graphene and an oxide capacitance of about 2.28-mu F/cm(2). It is found that for a rather large gate voltage range, this oxide capacitance is comparable; and sometimes even larger than the quantum capacitance of graphene. Since the total gate capacitance is determined by the smaller of the oxide and quantum capacitance, our results show that not much further Improvement can be gained via further vertical scaling down of the gate oxide, suggesting that Y2O3 may be the ultimate dielectric material for graphene. It is also shown; that the Y2O3 gate dielectric layer with EOT of 1.5 nm may also satisfy the ultimate lateral scaling requirement on the gate length of graphene FET and be Used effectively to control a graphene FET with a gate length as small as 1 nm.