Semiconductor device and manufacturing method thereof

摘要

To provide a miniaturized semiconductor device with stable electric characteristics in which a short-channel effect is suppressed. Further, to provide a manufacturing method of the semiconductor device. The semiconductor device (transistor) including a trench formed in an oxide insulating layer, an oxide semiconductor film formed along the trench, a source electrode and a drain electrode which are in contact with the oxide semiconductor film, a gate insulating layer over the oxide semiconductor film, a gate electrode over the gate insulating layer is provided. The lower corner portions of the trench are curved, and the side portions of the trench have side surfaces substantially perpendicular to the top surface of the oxide insulating layer. Further, the width between the upper ends of the trench is greater than or equal to 1 time and less than or equal to 1.5 times the width between the side surfaces of the trench.

主权项

1. A semiconductor device comprising:
an oxide insulating layer; a trench formed in the oxide insulating layer; an oxide semiconductor film in contact with a bottom portion and side portions of the trench, the oxide semiconductor film including indium, gallium, and zinc; a source electrode and a drain electrode electrically connected to the oxide semiconductor film; a gate insulating layer over the oxide semiconductor film; and a gate electrode over the gate insulating layer, wherein the side portions have side surfaces substantially perpendicular to a top surface of the oxide insulating layer, wherein a width between upper ends of the trench is greater than or equal to 1 time and less than or equal to 1.5 times a width between the side surfaces, wherein at least one of the bottom portion and a lower corner portion in which the bottom portion meets one of the side portions has a curved shape, and wherein a center of curvature of the curved shape is positioned in the oxide insulating layer.