Electrode chemistry impact on retention performance of ferroelectric hafnium zirconium oxide (Hf0.5Zr0.5O2− <i>x</i> ) capacitors
Abstract
Polarization retention of 10 nm thick ferroelectric hafnium zirconium oxide (Hf0.5Zr0.5O2−x, HZO) capacitors with W and TaN electrodes is investigated over temperatures ranging from 85 to 150 °C. Same state and opposite state polarization margins for devices with W electrodes show minimal retention loss after 105 at 150 °C. The devices capped with TaN electrodes show excellent same state retention, but the opposite state polarization margin in the TaN-electrode devices displays 40% retention loss at 150 °C after 105 s. The TaN-capped devices exhibit a more pronounced imprint, which is attributed to an increased oxygen vacancy content (compared to W-capped devices). The increased oxygen vacancy content in the TaN-capped devices is supported by photoluminescence and leakage current measurements. In addition, TaN-capped devices have chemically diffuse electrode–HZO interfaces; more abrupt interfaces are present in the W-capped devices. The presence of interfacial phases in the TaN-capped devices may lead to larger depolarization fields due to reduced charge screening. The results from this study provide further evidence that for HZO ferroelectric devices the electrode can significantly impact polarization retention behavior due to differences in oxygen vacancy concentration and formation of non-ferroelectric interfacial layers.
Article Details
Journal Info
Journal of Applied Physics
American Institute of Physics
Authors (14)
Benjamin L. Aronson
Department of Materials Science and Engineering, University of Virginia 1 , Charlottesville, Virginia 22904,
Ece Gunay
Department of Materials Science and Engineering
Sebastian Calderon
Nikhat Khan
Charles L. Brown Department of Electrical and Computer Engineering, University of Virginia 3 , Charlottesville, Virginia 22904,
Samantha T. Jaszewski
Department of Materials Science and Engineering, University of Virginia 1 , Charlottesville, Virginia 22904,
Megan K. Lenox
Department of Materials Science and Engineering, University of Virginia 1 , Charlottesville, Virginia 22904,
Fernando Vega
School of Mechanical Engineering and Birck Nanotechnology Center, Purdue University 1 , West Lafayette, 47907 Indiana,
Leonard Jacques
Department of Engineering Science and Mechanics, The Pennsylvania State University, N-246 Millennium Science Complex 1 , University Park, Pennsylvania 16802,
Helge H. Heinrich
Nanoscale Materials Characterization Facility, University of Virginia 6 , Charlottesville, Virginia 22904,
Nikhil Shukla
Department of Electrical and Computer Engineering, University of Virginia 1 , Charlottesville, Virginia 22904,
Susan Trolier-McKinstry
Thomas E. Beechem
School of Mechanical Engineering and Birck Nanotechnology Center, Purdue University 4 , West Lafayette, Indiana 47907,
Elizabeth C. Dickey
Jon F. Ihlefeld
Department of Materials Science and Engineering, University of Virginia 2 , Charlottesville, Virginia 22904,