Finfet structure and manufacture method

A method for forming a FinFET device, the method comprising:

• providing a substrate including a silicon substrate, a buried oxide layer, a first semiconductor material layer, stacked from bottom to top;
• forming a hard mask layer having a pattern of fins on a first semiconductor material layer, and removing a portion of the first layer of semiconductor material using the hard mask as an etch mask;
• forming side wall spacers on the side walls of the first semiconductor material layer and the hard mask layer;
• performing angled oxygen ion implantation to the surface of the first semiconductor material layer that is exposed at both sides of the side wall spacers, the implant being carried out at a first incline angle;
• performing an annealing process to form oxide diffusion regions in a first semiconductor material layer;
• removing the oxide diffusion regions to form recessed regions in the first semiconductor material layer;
• removing the portions of the first semiconductor material layer that is not shielded by the hard mask layer and the side wall spacers to expose the buried oxide layer below;
• and
• removing the hard mask layer and the side wall spacers to form a fin structure having recessed regions on the sides of the fin, the recessed regions having openings facing away from the fin structure.