Solid-State Electronics, Vol.51, No.11-12, 1508-1514, 2007
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(-1) cm(-2) 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 similar to 10(6), mainly due to low OFF current, and peak channel mobility around 80cm(2)/V s. The n-FETs, although functional, show inferior performance producing ON currents an order of magnitude lower compared to p-FETs. (C) 2007 Elsevier Ltd. All rights reserved.