The disclosure provides a FDSOI semiconductor structure and methods to fabricate it. The structure includes source and drain regions and gates respectively in an NMOS area and a PMOS area, a first oxide film layer formed on sidewalls of the source and drain contact holes, a metal layer deposited to fill the source and drain contact holes, a second oxide film layer formed on sidewalls of the gate contact holes, a metal layer deposited to fill the gate contact holes. Further the method includes growing an oxide film layer on the sidewalls of the contact holes between completing the contact etching process and filling the contact holes with the metal layer, followed by removing with etching the oxide film layer from the gates. Sizes of contact holes can be adjusted thereby.