Drive current enhancement of Si MOSFETs by using anti-ferroelectric gate insulators

• Published in: Japanese Journal of Applied Physics 2019-04, Vol.58 (SB), p.SBBA15
• Main Authors: Yamaguchi, Masashi, Gotow, Takahiro, Takenaka, Mitsuru, Takagi, Shinichi
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/1347-4065/ab073b

Si MOSFETs with anti-ferroelectric (AFE) gate insulators are expected to improve drive current without any hysteresis of off-currents at a gate voltage of 0 V. The contribution of AFE gate insulators to the on-current (Ion) of Si MOSFETs is examined using simulations based on simple analytical models of polarization-electric field (P-E) characteristics. Improvement in Ion would not be expected given the experimental AFE characteristics of Hf1−xZrxO2 (HZO) reported so far because the switching polarization (PAFE-FE) is too high. On the other hand, a minor loop of the P-E characteristics of HZO can increase Ion without any hysteresis in the off-current. Also, when the value obtained by dividing PAFE-FE by the elementary charge (PAFE-FE/q) is ∼1-2 × 1013 cm−2, AFE gate insulators are expected to significantly improve the drive current of Si MOSFETs and suppress a significant increase in the gate leakage current, because the polarization switch associated with the transition from the AFE to the FE phase can enhance the surface carrier concentration of inversion layers as well as reverse the direction of the slope of the band edge of the insulators.