Title :
Improving channel carrier mobility and immunity to charge trapping of high-K NMOSFET by using stacked Y/sub 2/O/sub 3//HfO/sub 2/ gate dielectric
Author :
Zhu, Feng ; Rhee, Se Jong ; Kang, Chang Yong ; Choi, Chang Hwan ; Akbar, Mohammad S. ; Krishnan, Siddarth A. ; Zhang, Manhong ; Kim, Hyoung-Sub ; Tackwhi Lee ; Ok, Injo ; Lee, Tackwhi
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Texas, Austin, TX, USA
Abstract :
A stacked Y/sub 2/O/sub 3//HfO/sub 2/ multimetal gate dielectric with improved electron mobility and charge trapping characteristics is reported. Laminated hafnium and yttrium were sputtered on silicon followed by post-deposition anneal (PDA) in N/sub 2/ ambient. The new dielectric shows a similar scalability to HfO/sub 2/ reference. Analysis on flatband voltage shift indicates positive fixed charge induced by Y/sub 2/O/sub 3/. Excellent transistor characteristics have been demonstrated. Stacked Y/sub 2/O/sub 3//HfO/sub 2/, compared to HfO/sub 2/ reference with similar equivalent oxide thickness (EOT), shows 49% enhancement in transconductance and 65% increase in the peak electron mobility. These improvements may be attributed to better charge trapping characteristics of the multimetal dielectric.
Keywords :
MOSFET; annealing; dielectric materials; electron mobility; electron traps; elemental semiconductors; hafnium compounds; high-k dielectric thin films; silicon; sputtered coatings; yttrium compounds; Y/sub 2/O/sub 3/-HfO/sub 2/-Si; channel carrier mobility; charge trapping immunity; electron mobility; flatband voltage shift; high-K NMOSFET; multimetal gate dielectrics; post-deposition annealing; sputtered coatings; stacked gate dielectrics; transconductance; Annealing; Electron mobility; Electron traps; Hafnium oxide; High K dielectric materials; High-K gate dielectrics; MOSFET circuits; Scalability; Silicon; Yttrium; Channel carrier mobility; HfO; MOSFET; Y; charge trapping; fixed charge; flatband voltage; leakage current density; multimetal oxide;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2005.859637
