Kanaki Toshiki, Yamasaki Hiroki, Koyama Tomohiro, Chiba Daichi, Ohya Shinobu, Tanaka Masaaki
Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo, 113-8656, Japan.
Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo, 113-8656, Japan.
Sci Rep. 2018 May 8;8(1):7195. doi: 10.1038/s41598-018-24958-z.
A vertical spin metal-oxide-semiconductor field-effect transistor (spin MOSFET) is a promising low-power device for the post scaling era. Here, using a ferromagnetic-semiconductor GaMnAs-based vertical spin MOSFET with a GaAs channel layer, we demonstrate a large drain-source current I modulation by a gate-source voltage V with a modulation ratio up to 130%, which is the largest value that has ever been reported for vertical spin field-effect transistors thus far. We find that the electric field effect on indirect tunneling via defect states in the GaAs channel layer is responsible for the large I modulation. This device shows a tunneling magnetoresistance (TMR) ratio up to ~7%, which is larger than that of the planar-type spin MOSFETs, indicating that I can be controlled by the magnetization configuration. Furthermore, we find that the TMR ratio can be modulated by V. This result mainly originates from the electric field modulation of the magnetic anisotropy of the GaMnAs ferromagnetic electrodes as well as the potential modulation of the nonmagnetic semiconductor GaAs channel layer. Our findings provide important progress towards high-performance vertical spin MOSFETs.
垂直自旋金属氧化物半导体场效应晶体管（自旋MOSFET）是后缩放时代一种很有前景的低功耗器件。在此，我们使用具有GaAs沟道层的基于铁磁半导体GaMnAs的垂直自旋MOSFET，展示了通过栅源电压V对漏源电流I进行的大幅调制，调制比高达130%，这是迄今为止垂直自旋场效应晶体管所报道的最大值。我们发现，GaAs沟道层中通过缺陷态的间接隧穿所受的电场效应是造成大电流I调制的原因。该器件显示出高达约7%的隧穿磁电阻（TMR）比，这比平面型自旋MOSFET的TMR比更大，表明电流I可以由磁化配置控制。此外，我们发现TMR比可以由V调制。这一结果主要源于GaMnAs铁磁电极磁各向异性的电场调制以及非磁性半导体GaAs沟道层的电势调制。我们的研究结果为高性能垂直自旋MOSFET取得了重要进展。
