Introduction of crystalline high- k gate dielectrics in a CMOS process

Abstract

In this work we report on methods to introduce crystalline rare-earth (RE) oxides with high ( k > 3.9) dielectric constants (high- k) in a CMOS process flow. Key process steps compatible with crystalline praseodymium oxide (Pr 2O 3) high- k gate dielectric have been developed and evaluated in metal-oxide-semiconductor (MOS) structures and n-MOS transistors fabricated in an adapted conventional bulk process. From capacitance–voltage measurements a dielectric constant of k = 36 has been calculated. Furthermore an alternative process sequence suitable for the introduction of high- k material into silicon on insulator (SOI) MOS-field-effect-transistors (MOSFET) is presented. The feasibility of this process is shown by realization of n- and p-MOSFETs with standard SiO 2 gate dielectric as demonstrator. SiO 2 gate dielectric can be replaced by crystalline RE-oxides in the next batch fabrication.