Effect of Vsub and Positive Charge in Buried Oxide on Super Steep SS “PN Body-Tied SOI-FET” and Proposal of CMOS without Vsub Bias

We report the effect of the substrate bias (V
_sub
) and the positive charge (Q
_ox
) in the buried oxide (BOX) on P-channel / N-channel super steep subthreshold slope (SS) “PN Body-Tied (PNBT) SOI-FET”. The Q
_ox
in the BOX was evaluated with the specific test device. Removing the effect of the Q
_ox
and realizing the super steep SS, the necessity of V
_sub,
especially on P-channel, was systematically confirmed with measurements and simulations. It was founded out that the positive feedback by PNBT contributes to making the barrier height for reducing the leakage current and realizing the super steep SS, although the difference of the static barrier height is small only with V
_sub
and the Q
_ox
. We also propose modification on PNBT structure for realizing CMOS without V
_sub
bias.