In　this　work,　the　impact　of　well　doping　and　corresponding　body　bias　on　UTBB　MOSFETs　is　investigated.　The　ability　of　threshold　voltage　adjustment　is　evaluated.　The　results　indicate　that　well　doping　can　change　the　threshold　voltage　both　of　the　N　and　P　channel　UTBB　MOSFETs.　The　maximum　amplitude　for　a　typical　26　nm　gate　length　device　is　about　100　mV,　and　these　correspond　to　the　cases　of　devices　with　an　inverse　type　of　high　concentration　dopant.　The　body　bias　adjusts　the　threshold　voltage　at　a　rate　of　100-140　mV/V　for　the　UTBB　MOSFETs　with　a　well.　By　optimizing　well　doping　and　body　biasing,　multi-threshold-voltage　UTBB　MOSFETs　can　be　designed　and　optimized　for　lower　power　application.　©　2018　Chinese　Institute　of　Electronics.