Germanium FETs and capacitors with rare earth CeO2/HfO2 gates

Long channel Ge FETs and capacitors with CeO₂/HfO₂ /TiN gates were fabricated by photolithography and gate wet etch. Rare earth CeO₂ in direct contact with Ge was used as a passivating layer producing lowest D_it values in the mid 10 ¹¹ eV^-1cm² range. HfO₂ cap reduces leakage and improves equivalent oxide thickness scaling of the whole gate stack. The p-FETs show exceptionally high I_ON/I _OFF ratio ~10⁶, mainly due to low off current, and peak channel mobility around 80 cm²/Vs. The n-FETs, although functional, show inferior performance producing on currents an order of magnitude lower compared to p-FETs