Joint Seminar - HKUST, IEEE ED/SSC Joint Chapter
Detection of Defect States in Capacitors with Ultra-thin Ta2O5 Films for DRAM Applications by Aero-Bias Thermally Stimulated Current Spectroscopy

by Prof. Wai Shing Lau, Department of Electrical and Electronic Engineering, Nanyang Technological University, Singapore

 :  07 Jul 2005 (Thu)
 :  2:00pm - 3:00pm
Venue  :  Room 1404, 1/F (Lifts 25-26), HKUST

Ultra-thin Ta2O5 films with relatively high dielectric constant (about 20-25) have attracted world-wide interest for DRAM applications. Defect states are expected to be responsible for leakage current in Ta2O5 capacitors. This seminar has two parts. Part I is about how to detect the oxygen vacancy double donors efficiently in ultra-thin Ta2O5 films (thickness < 10 nm) by zero-bias thermally stimulated current (ZBTSC) spectroscopy. Besides oxygen vacancy double donors, Si-O-vacancy-complex and C-O-vacancy-complex are also important defect states detected by ZBTSC . Part II is about how to suppress the various kinds of defect states in Ta2O5 capacitors.

Dr. WS Lau got his PhD in Electrical Engineering from the Pennsylvania State University in 1987. In 1988, he joined the National University of Singapore as a Lecturer. Subsequently he was promoted to Senior Lecturer. In 1997, he joined Chartered Semiconductor as a Senior Principal Engineer. Later he joined the Nanyang Technological University as Associate Professor in 2001. His research interest is in high-k dielectric materials, CMOS process and device engineering and also III-V semiconductor microwave devices.


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