Effect of Al-diffusion-induced positive flatband voltage shift on the electrical characteristics of Al-incorporated high-k metal-oxide-semiconductor field-effective transistor
Effect of Al-diffusion-induced positive flatband voltage shift on the electrical characteristics of Al-incorporated high-k metal-oxide-semiconductor field-effective transistor
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DOI：
10.1063/1.3093892
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发表时间：
2009-03
影响因子：
3.2
通讯作者：
Wenwu Wang;K. Akiyama;W. Mizubayashi;T. Nabatame;H. Ota;A. Toriumi
中科院分区：
文献类型：
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作者：
Wenwu Wang;K. Akiyama;W. Mizubayashi;T. Nabatame;H. Ota;A. Toriumi
我们系统地研究了高k介质中Al的扩散对掺铝高k栅堆栈的平带电压(VfB)的影响。报道了一种随着高k栅层的等效氧化层厚度(EOT)减小而出现反常正移的FIN VfB。在铝掺杂的HfxAl1−xOy栅极堆栈中，当SiO_2界面层被积极减薄时，Vfb首先位于众所周知的线性Vfb-Eot图上，并偏离正电压方向(Vfb上滚)，然后向负电压移动(Vfb下滚)。结果表明，VfB的上卷行为显著降低了p型金属氧化物半导体场效应晶体管(p-MOSFET)的阈值电压(Vth)，并且不会引起空穴迁移率特性的严重退化。VfB的上卷行为不依赖于栅极材料，但强烈依赖于高k介质，这归因于SiO_2/Si界面附近固定电荷的变化，这是Al从Hf_xAl_1-−_xO_y通过SiO_2扩散到SiO_2/Si界面的结果。这些结果表明，在定量调整薄EOT区的VfB时，应考虑VfB的反常正移，即VfB的上卷，并可用于进一步调整p-MOSFET中的Vth。我们系统地研究了高k介质中的Al扩散对Al掺杂的高k栅堆叠的平带电压(VfB)的影响。报道了一种随着高k栅层的等效氧化层厚度(EOT)减小而出现反常正移的FIN VfB。在铝掺杂的HfxAl1−xOy栅极堆栈中，当SiO_2界面层被积极减薄时，Vfb首先位于众所周知的线性Vfb-Eot图上，并偏离正电压方向(Vfb上滚)，然后向负电压移动(Vfb下滚)。结果表明，VfB的上卷行为显著降低了p型金属氧化物半导体场效应晶体管(p-MOSFET)的阈值电压(Vth)，并且不会引起空穴迁移率特性的严重退化。VfB的卷曲行为不依赖于栅极材料，但强烈依赖于高k介质，这归因于SiO_2/Si界面附近固定电荷的变化。
We systematically studied what effect Al diffusion from high-k dielectrics had on the flatband voltage (Vfb) of Al-incorporated high-k gate stacks. An anomalous positive shift fin Vfb with the decreasing equivalent oxide thickness (EOT) of high-k gate stacks is reported. As the SiO2 interfacial layer is aggressively thinned in Al-incorporated HfxAl1−xOy gate stacks with a metal-gate electrode, the Vfb first lies on the well known linear Vfb-EOT plot and deviates toward the positive-voltage direction (Vfb roll-up), followed by shifting toward negative voltage (Vfb roll-off). We demonstrated that the Vfb roll-up behavior remarkably decreases the threshold voltage (Vth) of p-type metal-oxide-semiconductor field-effect transistors (p-MOSFETs), and does not cause severe degradation in the characteristics of hole mobility. The Vfb roll-up behavior, which is independent of gate materials but strongly dependent on high-k dielectrics, was ascribed to variations in fixed charges near the SiO2/Si interface, which are caused by Al diffusion from HfxAl1−xOy through SiO2 to the SiO2/Si interface. These results indicate that anomalous positive shift in Vfb, i.e., Vfb roll-up, should be taken into consideration in quantitatively adjusting Vfb in thin EOT regions and that it could be used to further tune Vth in p-MOSFETs.We systematically studied what effect Al diffusion from high-k dielectrics had on the flatband voltage (Vfb) of Al-incorporated high-k gate stacks. An anomalous positive shift fin Vfb with the decreasing equivalent oxide thickness (EOT) of high-k gate stacks is reported. As the SiO2 interfacial layer is aggressively thinned in Al-incorporated HfxAl1−xOy gate stacks with a metal-gate electrode, the Vfb first lies on the well known linear Vfb-EOT plot and deviates toward the positive-voltage direction (Vfb roll-up), followed by shifting toward negative voltage (Vfb roll-off). We demonstrated that the Vfb roll-up behavior remarkably decreases the threshold voltage (Vth) of p-type metal-oxide-semiconductor field-effect transistors (p-MOSFETs), and does not cause severe degradation in the characteristics of hole mobility. The Vfb roll-up behavior, which is independent of gate materials but strongly dependent on high-k dielectrics, was ascribed to variations in fixed charges near the SiO2/Si interface, which ar...