Multi-gate metal oxide silicon transistors and methods of making multi-gate metal oxide silicon transistors are provided. The multi-gate metal oxide silicon transistor contains a bulk silicon substrate containing one or more convex portions between shallow trench regions; one or more dielectric portions over the convex portions; one or more silicon fins over the dielectric portions; a shallow trench isolation layer in the shallow trench isolation regions; and a gate electrode. The upper surface of the shallow trench isolation layer can be located below the upper surface of the convex portion, or the upper surface of the shallow trench isolation layer can be located between the lower surface and the upper surface of first dielectric layer. The multi-gate metal oxide silicon transistor can contain second spacers adjacent to side surfaces of the convex portions in a source/drain region.