A novel SOI (silicon on insulator) substrate is proposed for RF switch and LNA device performance enhancement. The OI (oxygen insertion)-Si layer and the subsequent undoped Si layer epitaxially grown on a thin SOI starting substrate effectively retain boron in the SOI layer to enable formation of a SSR (super-steep retrograde) channel profile in a regular CMOS flow. The new SSROI substrate reduces body resistance for power handling improvement of RF switch, in addition to reducing the surface channel doping and thus impurity scattering for cutoff frequency improvement of LNA devices.
