Chang Wen Hsin, Hatayama Shogo, Saito Yuta, Okada Naoya, Endo Takahiko, Miyata Yasumitsu, Irisawa Toshifumi
Semiconductor Frontier Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8568, Japan.
Research Center for Green X-Tech, Tohoku University, 6-6-11, Aoba-Yama, Aoba-Ku, Sendai, 980-8579, Japan.
Sci Rep. 2024 Nov 19;14(1):28572. doi: 10.1038/s41598-024-79750-z.
Novel van der Waals (vdW) contacts formed by layered BiTe are found effective in improving the performance of WSe pMOSFETs. As compared with conventional transition metal-based Ni/Au S/D contacts, over 10 times on-state current improvement is achieved. vdW interface formation between BiTe and WSe is confirmed by X-ray diffraction analysis and scanning transmission electron microscope observation. An atomically flat BiTe/WSe vdW interface, where the number of defects could be reduced as small as possible, contributes to the suppression of Fermi-level pinning caused by defect-induced gap states. Moreover, the semimetal-like characteristics of BiTe are also effective in minimizing the impact of metal-induced gap states. These features offer WSe pMOSFETs with exceptional S/D junction characteristics, including suppressed off-state leakage and a higher on-off ratio. In addition, it is found that WSe pMOSFETs with BiTe S/D contacts have excellent thermal stability, maintaining device performance even after 400 °C annealing, which is very promising for CMOS back-end-of-line application. The layered tellurides, reconciling low contact resistance and high thermal stability, are promising, particularly from the perspective of their application in the manufacturing process.
由层状BiTe形成的新型范德华(vdW)接触被发现可有效提高WSe pMOSFET的性能。与传统的基于过渡金属的Ni/Au源漏(S/D)接触相比,导通状态电流提高了10倍以上。通过X射线衍射分析和扫描透射电子显微镜观察证实了BiTe和WSe之间vdW界面的形成。原子级平整的BiTe/WSe vdW界面,其中缺陷数量可尽可能减少,有助于抑制由缺陷诱导的能隙态引起的费米能级钉扎。此外,BiTe的类半金属特性也有效地最小化了金属诱导能隙态的影响。这些特性为WSe pMOSFET提供了优异的S/D结特性,包括抑制的关态泄漏和更高的开/关比。此外,发现具有BiTe S/D接触的WSe pMOSFET具有出色的热稳定性,即使在400°C退火后仍能保持器件性能,这对于CMOS后端应用非常有前景。层状碲化物兼具低接触电阻和高热稳定性,特别是从其在制造工艺中的应用角度来看,很有前景。