Abstract: A method for manufacturing a semiconductor-on-insulator (SeOI) chip comprises: a) providing a SeOI structure, b) building a plurality of isolated field effect transistors (FET) each comprising: —a preliminary gate above a channel region, the FETs from a first group having a first preliminary gate length and the FETs from a second group having a smaller second preliminary gate length, —a source region and a drain region, and —a source electrode and a drain electrode, c) removing at least the preliminary gates of the FETs from the second group, leaving access to channel regions of the FETs, d) thinning a top layer in channel regions of the FETs from the second group, the top layer in channel regions of the first group of FETs having a different thickness, and e) forming functional gates simultaneously on channel regions of the FETs whose preliminary gates were removed.