BESS: a source structure that fully suppresses the floating body effects in SOI CMOSFETs

The most serious problem preventing the widespread use of SOI CMOSFETs-the floating body effects-are almost fully suppressed by a new source structure. In an nMOSFET, this new structure can be represented by an equivalent circuit of a bipolar embedded source structure (BESS) just beneath the n⁺ source junction. In the source region, or p type (or n^--type) recombination centers are embedded in a low-impurity-diffusion region (the base) and acts as a collector of the excess body carriers. The low-impurity-source region lowers the diffusion potential barrier for holes at the source junction. The solid-phase epitaxial regrowth mechanism of the Si⁺ implanted amorphous SOI layer was studied and applied to fabricate a prototype of this device capable of symmetric source-drain operations with the same source-drain breakdown voltage as that of a bulk device