Patent ID: 7410840

Claim:
A method of forming a fully-depleted silicon-on-insulator (FD-SOI) transistor and a bulk transistor as part of an integrated circuit fabrication process, comprising: providing a silicon-on-insulator (SOI) substrate which comprises a layer of silicon material formed over a layer of insulating material which is in turn formed over a semiconductor substrate; forming a layer of oxide material over the layer of silicon material; forming a layer of nitride material over the layer of oxide material; patterning the layer of nitride material, the layer of oxide material, the layer of silicon material and at least some of the layer of insulating material to establish bulk regions wherein bulk transistors can be formed, and where the bulk regions separate the layer of silicon into silicon regions wherein fully depleted transistors can be formed; removing the layer of nitride material; growing an epitaxial material in the bulk regions; removing the layer of oxide material; thinning the silicon regions by growing a layer of oxide material which consumes silicon as part of the growth process; removing the grown layer of oxide material to reveal the thinned silicon regions; and forming a fully depleted transistor in a thinned silicon region and forming a bulk transistor in a bulk region.