Novel Localized-SOI MOSFET's Combining the Advantages of SOI and Bulk Substrates for Highly-Scaled Devices

In this paper two kinds of novel localized-SOI structure devices, named as Quasi-SOI MOSFET and source-drain -on-nothing(SDON)/source-drain-on-insulator (SDOI) MOSFET, are demonstrated which can combine the advantages of SOI and bulk substrates. In the Quasi-SOI structure with the source/drain regions quasi-surrounded with insulator and the channel region directly connected with the bulk substrate, short channel effects (SCE), parasitic capacitance and self-heating effects (SHE) can be effectively reduced. The problem of degraded mobility and increased threshold voltage due to ultra-thin body in UTB SOI MOSFET's can also be solved. A method to fabricate the Quasi-SOI MOSFET is put forward. Process-device co-simulation results further show good scaling capability and excellent heat dissipation of the Quasi-SOI devices. In the SDON/SDOI device with the recessed S/D extension regions and source-drain staying on the partially buried layers, the advantages of quasi-SOI MOSFET can be maintained with the parasitic capacitance further reduced and the fabrication technology basically compatible with the standard CMOS technology. The proposed two structures can be considered as good candidates for highly-scaled devices.