1. What do you mean under "polarized" - applied voltage, or doping type? (I think, you mean the former).
2. What do you mean under "bulk" - body of SOI MOSFET, or substrate region under BOX?
3. is this FDSOI or PDSOI? (i.e., fully depleted or partially depleted?).
1. What do you mean under "polarized" - applied voltage, or doping type? (I think, you mean the former).
2. What do you mean under "bulk" - body of SOI MOSFET, or substrate region under BOX?
3. is this FDSOI or PDSOI? (i.e., fully depleted or partially depleted?).
Applied voltage varies with technology and application environment.
Ground (or negative rail) is common, but SOI technologies meant for
space and other radiation environments may apply a more negative
potential (which might then risk turning on the PMOS back channel,
there's a "BOX bias box").
In FDSOI technologies, adaptive back bias (voltage applied to substrate or well under BOX) is a popular and common technique to control leakage vs performance tradeoff.
Positive voltage will lower Vt for nMOSFET, and increase its ON current.
When device / block goes to off state, bias can be zero or negative.