The demonstration of colossal magneto-capacitance and “negative” capacitance effect with the promising characteristics of Jg-EOT and transistor´s performance on Ge (100) n-FETs by the novel magnetic gate stack scheme design

Super Jg-EOT gate stack characteristics, ultra-high κ value, and the promising transistor´s performance are achieved on the Ge n-FET by the application of the BaTiO₃ as the gate dielectric and the magnetic FePt film as the metal gate. The super C_gate/κ-value is generated by more dipoles in the HK dielectric layer with the coupling of the build-in magnetic field from MG (HK: BaTiO₃; MG: magnetic FePt). With the demonstration of this classical “colossal magneto-capacitance” effect in this work, the κ value can be improved ~175% successfully together with the reduction of Jg ~100X and the I_on is improved ~50% accordingly. On the other hand, the “negative” capacitance effect, which is important for the future steeper sub-threshold swing (S.S) device design, is also observed. The novel gate stack scheme (BaTiO₃ HK+ FePt MG), proposed in this work, with the super Jg-EOT characteristics, “negative” capacitance phenomenon, and the promising transistor´s performance on the high mobility (Ge) material provides the useful solution for the future low power mobile device design.