US Patent 7384842 Methods involving silicon-on-insulator trench memory with implanted plate

A method for fabricating silicon-on-insulator (SOI) trench memory includes forming a trench on a substrate, wherein a buried oxide layer is disposed on the substrate, a SOI layer is disposed on the buried oxide layer, and a hardmask layer is disposed on the SOI layer, implanting ions into the substrate and the SOI layer on a first opposing side of the trench and a second opposing side the trench to partially form a capacitor, depositing a node dielectric in the trench, filling the trench with a first polysilicon, removing a portion of the first polysilicon from the trench, removing an exposed portion of the node dielectric, filling the trench with a second polysilicon, masking to define an active region on the hardmask layer, forming shallow trench isolation (STI) such that the STI contacts a portion of the buried oxide layer, removing the hardmask layer, and forming a transistor.