SOI device structures with doped regions providing charge sinking

A method comprising:

• forming a plurality of trench isolation regions that extend through a device layer and a buried oxide layer of a silicon-on-insulator wafer into a substrate of the silicon-on-insulator wafer, wherein the trench isolation regions arranged to surround an active device region of the device layer, and the active device region is located over a portion of the buried oxide layer surrounded by the trench isolation regions;
• forming an implantation mask over the active device region;
• implanting the substrate with ions, with the implantation mask over the active device region and a blocked region in the substrate beneath the portion of the buried oxide layer, to form a well having a first conductivity type and a first electrical resistivity that is arranged in the substrate outside of the trench isolation regions;
• and
• forming a first doped region of the first conductivity type that is arranged in a first portion of the blocked region under the portion of the buried oxide layer and adjacent to one of the trench isolation regions,
• wherein the blocked region has a second electrical resistivity that is greater than the first electrical resistivity, and the first doped region is more heavily doped with a dopant of the first conductivity type than the blocked region.