The present 14 volts automotive electrical system will
soon become 42 volts. For these future automotive applications, development
of 80 volts power MOSFETs exhibiting low on-resistance is desired. The
“FLoating Island” MOSFET (FLIMOSFET) is one of the new candidates to break
the silicon limit, which is the “specific on-resistance/breakdown
voltage” trade-off limit of conventional power MOSFETs. In this paper, the
“FLoating Island” concept has been implemented on silicon: new vertical
N-channel FLIMOSFETs (FLYMOS™) dedicated to automotive
applications (below 100 volts) have been fabricated for the first time,
using two steps epitaxy process. Experimental results show that the
FLYMOS™ transistor exhibit a breakdown voltage of 73 volts
but also an improved specific on-resistance compared to conventional
VDMOSFETs (33% reduction of the specific on-resistance for the same
breakdown voltage). In other words, in terms of “specific on-resistance/breakdown voltage” trade-off, the FLYMOS™ transistor is one
of the best MOS devices in low voltage applications. These measurements
validate the “FLoating Island” concept and the efficiency of the original
edge cell that is used in the FLYMOS™ technology.