Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871, China.
Nanoscale. 2018 Oct 21;10(39):18492-18501. doi: 10.1039/c8nr05680c. Epub 2018 Aug 22.
Quasi-one-dimensional semiconducting materials have attracted increasing attention due to their excellent ability to downscale the size of transistors. However, in quasi-one-dimensional nanowire (NW) transistors, their surface and interface properties play a very important role mainly due to the large surface-to-volume ratio of NWs and surface scattering, which degrade their carrier mobility. Herein, we developed a new method to cover the channel surface of InAs NW field effect transistors (FETs) with YO/HfO layers to improve their electrical properties. We successfully fabricated nine FETs and measured their electrical properties, which improve after depositing the YO/HfO layers, including an increase in on-state current, decrease in off-state current, increase in transconductance, increase in electron mobility and decrease in subthreshold swing. By comparing the properties of YO/HfO-covered devices with that of the FETs fabricated without the YO covering or without annealing, we prove that it is the combined YO/HfO layers instead of only the YO or HfO layer that improve the electrical properties of the FETs. The Cs-corrected high-resolution scanning transmission electron microscopy study demonstrates that Y can actually diffuse through the native oxide layer (confirmed to be InO) and reach the surface of the InAs NWs. Our results indicate that the desirable characteristics of YO and the surface passivation by HfO improve the electrical properties of the InAs NW FETs, in which YO plays an important role to modify and stabilize the interface between the InAs NWs and the outside dielectric layer. Furthermore, this method should also be applicable to other III-V materials.
准一维半导体材料由于具有出色的晶体管尺寸缩小能力而受到越来越多的关注。然而，在准一维纳米线（NW）晶体管中，由于 NW 的大表面积与体积比和表面散射，其表面和界面特性起着非常重要的作用，这会降低它们的载流子迁移率。在此，我们开发了一种新方法，用 YO/HfO 层覆盖 InAs NW 场效应晶体管（FET）的沟道表面，以改善其电学性能。我们成功制备了 9 个 FET，并测量了它们的电学性能，沉积 YO/HfO 层后，这些性能得到了改善，包括导通电流增加、关断电流减小、跨导增加、电子迁移率增加和亚阈值摆幅减小。通过比较涂覆有 YO/HfO 层的器件与未涂覆 YO 层或未经退火的 FET 的性能，我们证明是 YO/HfO 层的组合而不是单独的 YO 或 HfO 层改善了 FET 的电学性能。Cs 校正的高分辨率扫描透射电子显微镜研究表明，Y 实际上可以通过本征氧化层（被确认为 InO）扩散并到达 InAs NW 的表面。我们的结果表明，YO 的理想特性和 HfO 的表面钝化改善了 InAs NW FET 的电学性能，其中 YO 在修饰和稳定 InAs NW 与外部介电层之间的界面方面起着重要作用。此外，这种方法也应该适用于其他 III-V 材料。
