Title :
Dominant Layer for Stress-Induced Positive Charges in Hf-Based Gate Stacks
Author :
Zhang, Jian F. ; Chang, Mo Huai ; Ji, Zhigang ; Lin, Lin ; Ferain, Isabelle ; Groeseneken, Guido ; Pantisano, Luigi ; De Gendt, Stefan ; Heyns, Marc M.
Author_Institution :
Sch. of Eng., Liverpool John Moores Univ., Liverpool
Abstract :
Positive charges in Hf-based gate stacks play an important role in the negative bias temperature instability of pMOSFETs, and their suppression is a pressing issue. The location of positive charges is not clear, and central to this letter is determining which layer of the stack dominates positive charging. The results clearly show that positive charges are dominated by the interfacial layer (IL) and that they do not pile up at the HfSiON/IL interface. The results support the assumption that positive charges are located close to the IL/substrate interface. Unlike electron trapping that reduces rapidly for thinner Hf dielectric layer, positive charges cannot be reduced by using a thinner HfSiON film.
Keywords :
MOSFET; dielectric materials; hafnium compounds; stability; Hf-based gate stacks; HfSiON; IL/substrate interface; dielectric layer; dominant layer; interfacial layer; negative bias temperature instability; pMOSFET; stress-induced positive charges; Dielectric substrates; Electron traps; Hafnium; Interface states; MOSFETs; Negative bias temperature instability; Niobium compounds; Pressing; Pulse measurements; Titanium compounds; Hf silicates; high-$k$ gate dielectric; instability; negative bias temperature instability (NBTI); positive charges; reliability; spatial distribution;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2008.2006288
