The invention discloses a manufacturing method of a three-dimensional array grid-last type Si-NWFET (
Silicon-
Nanowire Field Effect Transistor) based on an SOI (
Silicon On Insulator). The manufacturing method comprises the following steps of: alternatively growing
silicon layers and
germanium-
silicon layers on the SOI, forming a fin-shaped active region, forming
silicon nanowires in the fin-shaped active region, depositing
amorphous carbon in a groove as a virtual isolating layer, then carrying out a grid-last process, and finally and simultaneously carrying out deposition on a groove isolating medium and an interlayer isolating medium. The manufacturing method disclosed by the invention has the advantages that due to existence of an
oxygen embedding layer in the SOI, the isolating effect between a grid and an
SOI substrate is effectively improved, and the adoption of the grid-last process is beneficial to the control of the profile of the grid and the electrical property of a device; the utilization of the
amorphous carbon as the virtual isolating layer is beneficial to the control of the profiles of the grid and the grid groove; and in addition, the silicon-
nanowire field effect transistor (Si-NWFET) structure is designed by adopting a three-dimensional array silicon-
nanowire structure, so that the number of the nanowires is increased, and the current driving capability of the device is improved.