Title :
Interface properties of Hf-based high-k gate dielectrics —O vacancies and interface reaction—
Author :
Shiraishi, Kenji
Author_Institution :
Univ. of Tsukuba, Tsukuba
Abstract :
We have investigated, theoretically the cause of the substantial threshold voltage (Vth) shifts observed in Hf-related high-k gate stacks with p+poly-Si and p-metal gates, by focusing on the ionic nature of HfO2. The oxygen vacancy (Vo) level in ionic HfO2 is located in a relatively higher part of the band gap. This high position of the VO results in a significant elevation of the Fermi level for p+poly-Si and p-metal gates, if Si can interact with high-k HfO2. Vo formation in the HfO2 induces a subsequent electron transfer from HfO2 to gates, causing a substantial Vth shifts in MISFETs.
Keywords :
Fermi level; MIS structures; MISFET; hafnium compounds; high-k dielectric thin films; Fermi level pinning; HfO2; MISFET; high-k gate dielectric; interface property; interface reaction; oxygen vacancy; p+poly-Si gate; p-metal gate; substantial threshold voltage shift; Channel bank filters; Dielectric substrates; Electrons; Hafnium oxide; High K dielectric materials; High-K gate dielectrics; Large scale integration; Leakage current; MISFETs; Threshold voltage; Fermi level pinning; High-k HfO2 dielectrics; Oxygen vacancy; poly-Si and metal gates; send a blank e-mail to shiraishi@comas.frsc.tsukuba.ac.jp;
Conference_Titel :
Physics of Semiconductor Devices, 2007. IWPSD 2007. International Workshop on
Conference_Location :
Mumbai
Print_ISBN :
978-1-4244-1728-5
Electronic_ISBN :
978-1-4244-1728-5
DOI :
10.1109/IWPSD.2007.4472450
