Precise determination of metal effective work function and fixed oxide charge in MOS capacitors with high-κ dielectric

Abstract Effective metal work function, Φ m,eff , and oxide charge, Q ox , were determined on MOS capacitors with slanted high- κ dielectric. Φ m,eff and Q ox were extracted using flat-band voltage shift versus equivalent oxide thickness data, both deduced from the capacitance–voltage measurements. Slanted HfSiO x dielectric (initial thickness was 9 nm) was prepared by gradual etching in HF-based solution. As a metal electrode, thin Ru-films were deposited by MOCVD-derived technique—Atomic Vapor Deposition ® on the slanted HfSiO x as well as SiO 2 dielectrics. The Φ m,eff of Ru was found to be 4.74 and 4.81 eV for Ru/HfSiO x and Ru/SiO 2 gate stacks, respectively. Ultraviolet photoelectron spectroscopy yields the work function of 4.62 eV in agreement with the capacitance–voltage data. We also studied the I–V characteristics of the Ru/HfSiO x /Si MOS capacitors. The barrier height was found to be constant within the HfSiO x bulk.

[1]  Michel Houssa,et al.  High-? Gate Dielectrics , 2004 .

[2]  S. Ferrari,et al.  Ru and RuO2 gate electrodes for advanced CMOS technology , 2004 .

[3]  F. Roozeboom,et al.  Application of Ru-based gate materials for CMOS technology , 2004 .

[4]  P. T. Lai,et al.  Conduction mechanisms in MOS gate dielectric films , 2004, Microelectron. Reliab..

[5]  S. M. Sze,et al.  Physics of semiconductor devices , 1969 .

[6]  Luigi Pantisano,et al.  Ruthenium gate electrodes on SiO2 and HfO2: Sensitivity to hydrogen and oxygen ambients , 2006 .

[7]  H. Waard,et al.  Ruthenium films by digital chemical vapor deposition: Selectivity, nanostructure, and work function , 2004 .

[8]  Qiang Sun,et al.  Hydrogen adsorption at RuO2(110): Density-functional calculations , 2004 .

[9]  Lothar Frey,et al.  Electrical properties of hafnium silicate films obtained from a single-source MOCVD precursor , 2005, Microelectron. Reliab..

[10]  R. Lamb,et al.  Ruthenium oxide and strontium ruthenate electrodes for ferroelectric thin-films capacitors , 2000 .

[11]  Carlton M. Osburn,et al.  Impact of gate workfunction on device performance at the 50 nm technology node , 2000 .

[12]  J. Wortman,et al.  Modeling study of ultrathin gate oxides using direct tunneling current and capacitance-voltage measurements in MOS devices , 1999 .

[13]  D. Kwong,et al.  Thermal response of Ru electrodes in contact with SiO2 and Hf-based high-k gate dielectrics , 2005 .

[14]  K. Tong,et al.  Thermally grown ruthenium oxide thin films , 2004 .

[15]  J. Robertson.  Band offsets of wide-band-gap oxides and implications for future electronic devices , 2000 .

[16]  Chenming Hu,et al.  MOS capacitance measurements for high-leakage thin dielectrics , 1999 .

[17]  D. Schroder.  Semiconductor Material and Device Characterization , 1990 .