EOT of 0.62 nm and High Electron Mobility in La-silicate/Si Structure Based nMOSFETs Achieved by Utilizing Metal-Inserted Poly-Si Stacks and Annealing at High Temperature
EOT of 0.62 nm and High Electron Mobility in La-silicate/Si Structure Based nMOSFETs Achieved by Utilizing Metal-Inserted Poly-Si Stacks and Annealing at High Temperature
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DOI：
10.1109/ted.2011.2174442
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发表时间：
2012-02
影响因子：
3.1
通讯作者：
T. Kawanago;Yeonghun Lee;K. Kakushima;P. Ahmet;K. Tsutsui;A. Nishiyama;N. Sugii;K. Natori;T. Hattori;H. Iwai
中科院分区：
文献类型：
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作者：
T. Kawanago;Yeonghun Lee;K. Kakushima;P. Ahmet;K. Tsutsui;A. Nishiyama;N. Sugii;K. Natori;T. Hattori;H. Iwai
本文报道了直接接触的镧硅酸盐/硅界面结构的控制，其目的是实现缩放的等效氧化物厚度（EOT）和小的界面态密度。在800 °C下退火30 min，直接接触的La-Si/Si界面态密度降低到1.6 × 1011 cm-2 eV-1，而过量的硅酸盐反应同时导致EOT显著增加。通过利用金属插入多晶硅（MIPS）堆叠和它们在高温下的退火，EOT的增加被大大抑制。同时，由于MIPS叠层中的Si层防止了退火过程中过量氧从大气中扩散，因此获得了上级界面特性。结果表明，采用直接接触的硅酸镧/硅结构，在1 MV/cm时，有效电子迁移率为155 cm 2/V·s，EOT为0.62nm。这一结果与利用Hf基氧化物/Si结构所记录的有效电子迁移率相当。这证明了我们所提出的方法的优点，以实现缩放的EOT与一个上级界面性能的国家的最先进的金属氧化物半导体场效应晶体管。
This paper reports on the control of the direct-contact La-silicate/Si interface structure with the aim of achieving scaled equivalent oxide thickness (EOT) and small interface state density. The interface state density at the direct-contact La-silicate/Si interface is found to be reduced to 1.6 × 1011 cm-2eV-1 by annealing at 800 °C for 30 min in forming gas ambient, whereas excess silicate reaction concurrently induced a significant increase in EOT. By utilizing metal-inserted poly-Si (MIPS) stacks and their annealing at high temperature, the increase in EOT is drastically suppressed. At the same time, a superior interfacial property is obtained because the Si layer in the MIPS stacks prevents the excess oxygen diffusion from the atmosphere during the annealing process. As a result, the effective electron mobility of 155 cm2/V·s at 1 MV/cm and an EOT of 0.62 nm are successfully achieved by utilizing direct-contact La-silicate/Si structure. This result is comparable with the recorded effective electron mobility achieved by utilizing Hf-based oxides/Si structure. This demonstrates the advantage of our proposed method to realize the scaled EOT with a superior interfacial property for state-of-the-art metal-oxide-semiconductor field-effect transistors.