This work presents a thorough study of the impact of different Buried OXide (BOX) configurations on the scaling of extremely thin SOI devices (ET-FDSOI, also known as UTSOI) to sub-32 nm nodes using a Multi-Subband Ensemble Monte Carlo simulator (MS-EMC). Standard thick BOX, ultra thin BOX (UTBOX) and UTBOX with ground plane (UTBOX + GP) solutions have been considered in order to check their influence on Short Channel Effects (SCEs). Simulations show that for channel lengths shorter than 20 nm, silicon thickness thinner than 5 nm are needed to control Drain Induced Barrier Lowering (DIBL) below 100 mV/V. However, thickness variability and mobility reduction could play an important role for so small thickness. Nevertheless, we show that with the appropriate combination of UTBOX and GP it is possible to use thicker Si layers, even for channels shorter than 20 nm, and keeping SCEs under control, i.e., DIBL below 100 mV/V. (C) 2012 Elsevier Ltd. All rights reserved.