Title :
Hard and soft-breakdown characteristics of ultra-thin HfO/sub 2/ under dynamic and constant voltage stress
Author :
Kim, Y.H. ; Onishi, K. ; Kang, C.S. ; Choi, R. ; Cho, H.-J. ; Nieh, R. ; Han, J. ; Krishnan, S. ; Shahriar, A. ; Lee, J.C.
Author_Institution :
Dept. of Electr. & Comput. Eng., Texas Univ., Austin, TX, USA
Abstract :
HfO/sub 2/ with EOT of 14 /spl Aring/ shows soft and hard breakdown behavior which consists of different Weibull distributions, area scaling factors, and acceleration factors. The thickness dependence of HfO/sub 2/ Weibull slope /spl beta/ indicates that the breakdown mechanism of HfO/sub 2/ is intrinsic. Similar to SiO/sub 2/, a steeper voltage acceleration factor of HfO/sub 2/ has been observed as thickness decreases. Unipolar AC voltage stress on MOS capacitors results in larger lifetime compared to constant voltage stress. This may be due to lower overall charge trapping as a result of short "on time" compared to the transition time and charge detrapping during the off period. The higher the frequency of the AC stress, the longer the time-to-breakdown.
Keywords :
MOS capacitors; MOSFET; Weibull distribution; dielectric thin films; electric breakdown; hafnium compounds; 14 A; AC stress frequency; EOT; HfO/sub 2/-Si; MOS capacitors; MOSFETs; Weibull distributions; Weibull slope; acceleration factors; area scaling factors; charge detrapping during; constant voltage stress; dynamic voltage stress; hard breakdown characteristics; intrinsic breakdown mechanism; overall charge trapping; soft breakdown characteristics; thickness dependence; time-to-breakdown; transition time; ultra-thin HfO/sub 2/; unipolar AC voltage stress; Acceleration; Breakdown voltage; Dielectric breakdown; Electric breakdown; Electrodes; Hafnium oxide; High-K gate dielectrics; Leakage current; Stress; Weibull distribution;
Conference_Titel :
Electron Devices Meeting, 2002. IEDM '02. International
Conference_Location :
San Francisco, CA, USA
Print_ISBN :
0-7803-7462-2
DOI :
10.1109/IEDM.2002.1175918
