Invited Paper EM-TuA7
Bilayer High-k Gate Stacks on Ge and InGaAs

Tuesday, November 1, 2011, 4:00 pm, Room 210

Research on novel channel materials such as Ge and InGaAs for high performance MOSFETs prompts interest in alternative high permittivity gate dielectrics because the thermal stability requirements that led to the adoption of HfO₂-based high-k dielectrics on silicon are relaxed for such channels. We have focused recently on ALD-grown TiO₂/Al₂O₃ bilayer dielectrics that combine large band gap Al₂O₃ interfacial layers (1-2 nm in thickness) with physically thicker but very high k TiO₂ gate dielectrics as a means of scaling gate capacitance and gate leakage current. This bilayer structure relies on the electrical passivity of the Al₂O₃/channel interface to achieve high performance. This presentation will summarize the scaling potential of these bilayer dielectric structures and methods by which low defect density Al₂O₃/Ge and Al₂O₃/InGaAs interfaces can be prepared.