US Patent 7247530 Ultrathin SOI transistor and method of making the same

A method of fabricating an ultrathin SOI memory transistor includes preparing a substrate, including forming an ultrathin SOI layer of the substrate; adjusting the threshold voltage of the SOI layer; depositing a layer of silicon oxide on the SOI layer; patterning and etching the silicon oxide layer to form a sacrificial oxide gate in a gate region; depositing a layer of silicon nitride and forming the silicon nitride into a silicon nitride sidewall for the sacrificial oxide gate; depositing and smoothing a layer of amorphous silicon; selectively etching the sacrificial gate oxide; growing a layer of oxide in the gate region; depositing and smoothing a second layer of amorphous silicon; patterning and etching the second layer of amorphous silicon; implanting ion to form a source region and a drain region; annealing the structure; and depositing a layer of passivation oxide.