Title :
Roles of oxygen vacancy in HfO2/ultra-thin SiO2 gate stacks - Comprehensive understanding of VFB roll-off -
Author :
Akiyama, K. ; Wang, W. ; Mizubayashi, W. ; Ikeda, M. ; Ota, H. ; Nabatame, T. ; Toriumi, A.
Author_Institution :
MIRAI-ASET, AIST, Tsukuba
Abstract :
This paper discusses a role of the oxygen vacancy in HfO2/ultra-thin (UT) interfacial layer (IL) SiO2 gate stacks, focusing on the VFB roll-off. The metal/top-SiO2/HfO2/UT IL-SiO2/Si gate stacks have been studied. It is found for the first time that the VFB roll-off is eliminated by inserting 1~2 nm top-SiO2 between metal gate and HfO2. This elimination of the VFB roll-off is explained by compensating the bottom dipoles at HfO2/IL-SiO2 interface with the counter dipoles at top-SiO2/HfO2 interface. Therefore it is concluded that the bottom dipole is assigned to the dominant origin of the VFB roll-off.
Keywords :
MIS structures; hafnium compounds; silicon compounds; vacancies (crystal); HfO2-SiO2; MIS structures; bottom dipole; counter dipoles; oxygen vacancy; ultra-thin gate stacks; ultra-thin interfacial layer; Annealing; Channel bank filters; Counting circuits; Electrodes; Hafnium oxide; High K dielectric materials; High-K gate dielectrics; MOSFET circuits; Scalability; Tin;
Conference_Titel :
VLSI Technology, 2008 Symposium on
Conference_Location :
Honolulu, HI
Print_ISBN :
978-1-4244-1802-2
Electronic_ISBN :
978-1-4244-1803-9
DOI :
10.1109/VLSIT.2008.4588570
