Title :
Positive bias temperature instability effects of Hf-based nMOSFETs with various nitrogen and silicon profiles
Author :
Changhwan Choi ; Chang-Seok Kang ; Chang Yong Kang ; Se Jong Rhee ; Akbar, M.S. ; Krishnan, S.A. ; Manhong Zhang ; Lee, J.C.
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Texas, Austin, TX, USA
Abstract :
Positive bias temperature instability (PBTI) effects of HfO/sub 2/-based nMOSFETs with various nitrogen profiles in HfO/sub 2/ were investigated. The nitrogen profile was modulated by an inserting Si layer (/spl sim/6/spl Aring/) into hafnium oxynitride gate dielectrics. The Si layer is used to trap nitrogen and to suppress nitrogen out-diffusion during subsequent anneals. Compared to control HfO/sub x/N/sub y/ without Si insertion, the Si-inserted HfO/sub x/N/sub y/ samples exhibited reduced PBTI degradation, especially if the Si layer was placed further from the Si interface. The improvement can be attributed to the reduction of oxide bulk trapped as well as reduced interface trapped charge generation resulting from compensation effect of inserted Si layer.
Keywords :
MOSFET; annealing; dielectric materials; hafnium compounds; interface states; silicon; Hf-based nMOSFET; HfO/sub 2/; HfO/sub x/N/sub y/; PBTI effects; Si; charge pumping current; charge trapping characteristics; hafnium oxynitride gate dielectrics; interface trapped charge generation; nitrogen incorporated hafnium oxide; nitrogen out-diffusion; nitrogen profile; positive bias temperature instability effects; Annealing; Degradation; Dielectrics; Hafnium oxide; MOSFETs; Nitrogen; Semiconductor films; Silicon; Stress; Temperature; Charge pumping current; charge trapping characteristics; nitrogen incorporated hafnium oxide; positive bias temperature instability (PBTI);
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2004.840717
