Title :
Threshold voltage instability of ultra-thin HfO2 NMOSFETs: characteristics of polarity dependences
Author :
Rhee, Se Jong ; Kang, Chang Yong ; Kim, Young Hee ; Kang, Chang Seok ; Cho, Hag-Ju ; Choi, Rino ; Choi, Chang Hwan ; Akbar, M.S. ; Lee, Jack C.
Author_Institution :
Dept. of Electr. & Comput. Eng., Texas Univ., Austin, TX, USA
Abstract :
Threshold voltage instability characteristics of high-k HfO2 with SiON interface NMOSFETs under three different dynamic stress conditions, positive, negative, and bipolar stress, have been investigated for the first time. Frequency and duty cycle dependencies have been observed in all three conditions. In contrast to positive AC stress, negative dynamic stress showed decrease in the threshold voltage. Bipolar stress resulted in the highest threshold voltage shift, but the degradation in transconductance and subthreshold swing was actually smaller in comparison to those in negative unipolar stress. A plausible mechanism has been proposed.
Keywords :
MOSFET; dielectric polarisation; dielectric thin films; hafnium compounds; permittivity; semiconductor device testing; silicon compounds; HfO2-SiON; SiON interface NMOSFET; bipolar stress; duty cycle dependencies; dynamic stress conditions; frequency dependencies; high-k HfO2; negative dynamic stress; negative unipolar stress; polarity dependence; positive AC stress; subthreshold swing; threshold voltage instability; threshold voltage shift; transconductance degradation; ultra-thin HfO2 NMOSFET; Degradation; Dielectric materials; Frequency; Hafnium oxide; High K dielectric materials; High-K gate dielectrics; MOSFETs; Pulse measurements; Stress; Threshold voltage;
Conference_Titel :
Device Research Conference, 2004. 62nd DRC. Conference Digest [Includes 'Late News Papers' volume]
Print_ISBN :
0-7803-8284-6
DOI :
10.1109/DRC.2004.1367803
