Large current modulation and tunneling magnetoresistance change by a side-gate electric field in a GaMnAs-based vertical spin metal-oxide-semiconductor field-effect transistor

摘要

A vertical spin metal-oxide-semiconductor field-effect transistor (spinMOSFET) is a promising low-power device for the post scaling era. Here, using aferromagnetic-semiconductor GaMnAs-based vertical spin MOSFET with a GaAschannel layer, we demonstrate a large drain-source current IDS modulation by agate-source voltage VGS with a modulation ratio up to 130%, which is thelargest value that has ever been reported for vertical spin field-effecttransistors thus far. We find that the electric field effect on indirecttunneling via defect states in the GaAs channel layer is responsible for thelarge IDS 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 IDS can be controlled by the magnetization configuration.Furthermore, we find that the TMR ratio can be modulated by VGS. This resultmainly originates from the electric field modulation of the magnetic anisotropyof the GaMnAs ferromagnetic electrodes as well as the potential modulation ofthe nonmagnetic semiconductor GaAs channel layer. Our findings provideimportant progress towards high-performance vertical spin MOSFETs.