Title :
Work Function Investigation in Advanced Metal Gate-HfO2-SiO2 Systems with Bevel Structures
Author :
Kuriyama, Atsushi ; Faynot, Olivier ; Brévard, Laurent ; Tozzo, Amélie ; Clerc, Laurence ; Deleonibus, Simon ; Cristotoveanu, S. ; Mitard, Jérôme ; Vidal, Vincent ; Iwai, Hiroshi
Author_Institution :
CEA-LETI, Grenoble
Abstract :
This paper presents for the first time the extraction of chemical vapor deposition (CVD)-TiN and poly-Si work functions on atomic layer deposition (ALD)-HfO2 and high temperature SiO2 (HTO) for a wide range of EOT values. The measurements were performed on bevel oxide structures. Our results reveal that the work functions of both TiN and poly-Si gates highly depend on the underlying dielectrics especially in the case of TiN on HTO films likewise lower leakage currents depending on dielectric stacks. It is notable that when TiN is formed on the HTO film, its work function has two distinct values depending on the HTO thickness; this indicates that Ti-Si bonds strongly affect the work function variation. Both TiN on HTO and poly-Si on HfO 2 show the work function shifts to about 4.3 eV, suggesting a pinning level on both structures
Keywords :
Fermi level; atomic layer deposition; chemical vapour deposition; dielectric materials; hafnium compounds; metal-insulator boundaries; silicon compounds; tin compounds; work function; HTO film; HfO2-SiO2; SiO2; TiN; atomic layer deposition; bevel oxide structures; chemical vapor deposition; dielectric stacks; dielectrics; leakage currents; metal gate; pinning level; work function; Annealing; Atomic layer deposition; Chemical vapor deposition; Dielectric substrates; Hafnium oxide; High-K gate dielectrics; MOSFETs; Surface cleaning; Temperature distribution; Tin;
Conference_Titel :
Solid-State Device Research Conference, 2006. ESSDERC 2006. Proceeding of the 36th European
Conference_Location :
Montreux
Print_ISBN :
1-4244-0301-4
DOI :
10.1109/ESSDER.2006.307650
