Efficacy of body ties under dynamic switching conditions in partially depleted SOI CMOS technology

Historically, body ties have been designed using removal of DC floating-body (FB) effects (e.g., kink, breakdown voltage) as the main criteria. It has been implicitly assumed that the transient FB effects would be minimized too with such a tie. However, such body ties while “suppressing” DC effects, may not necessarily be effective in AC/transient conditions, since the body (dis)charging time constants may be much larger than desired. For example, in a digital SOI CMOS circuit, with the gate switching at a few tens of ps, the efficacy of the body tie may be little or none at all, depending on the response time τ_B(=R_BC_B) of the body. Hence, in order to design effective body ties in transients, dynamic (dis)charging effects due to R_B and C_B in the body must be included