Deep sub-micron SOI MOSFET with buried body strap

Reports on the implementation of a substrate contact in SOI consisting of a low resistance polysilicon strap within the buried oxide which contacts the SOI layer from the bottom. The efficacy of this buried strap is demonstrated in the grounded body SOI MOSFET. Various implementations of body contacts for SOI MOSFETs have been reported to alleviate problems associated with the floating body, such as the well-known kink and parasitic bipolar breakdown effects. The lateral body contact, which maintains device source/drain symmetry, has traditionally been limited in its effectiveness by the high resistance of the path that holes must travel laterally under the gate in order to reach the side contact. In this work, an effective lateral body contact, made possible by wafer bonding and etchback techniques, is demonstrated in deep sub-micron MOSFETs.