From Ferroelectric Materials to Enhanced Semiconductor Devices (06/03/24)
Speaker and Affliation:
Prof. Dr.-Ing. Thomas Mikolajick
NaMLab gGmbH and Chair of Nanoelectronics; TU Dresden
When?
6th March, 2024 (Wednesday), 04.00 PM (India Standard Time)
Where
KPA Auditorium, Dept. of Materials Engineering, IISc, Bangalore
Abstract
More than ever modern electronic systems require semiconductor memories [1]. The rapidly increasing use of artificial intelligence in electronic systems is a major driver to this trend [2]. At the same time, new physical storage mechanisms like ferroelectric polarization, magnetoresistance, phase change, and various resistive switching effects are receiving increasing attention due to the facts that traditional charge-based memory devices are facing serious scaling limits and become harder to integrate into modern high-performance CMOS processes that use high-k metal gate technology as well as non-planar device geometries [1]. Compare to the other mentioned options, ferroelectric polarization has two important unique selling points. First, the switching is field driven and, therefore, the energy required for writing is the lowest of all options that offer nonvolatility. Second, there are three fundamentally different options for the readout. Direct sensing of the switched charge in a ferroelectric capacitor (DRAM like sensing), coupling of the polarization to the gate of a field effect transistor (Flash like sensing) and modulation of the resistance of a tunnel junction (resistive switching like sensing) offering a high flexibility to taylor devices towards the application requirements while still using the same physical mechanism and material system. Well-known ferroelectric materials like lead zirconium titanate or strontium bismuth tantalate etc. are difficult to integrate into state-of-the-art electronic fabrication processes. About 15 years ago ferroelectricity in hafnium oxide was discovered and first published 12 years ago [3]. With this innovation, all of a sudden, a CMOS compatible ferroelectric material became available. Moreover, the recent discovery of ferroelectricity in AlScN [5] added a valuable option for compound semiconductor technologies based on GaN.
The talk will first explain the approach to realize ferroelectric hafnium oxide based materials of high quality including recent advances. Based on this the status of integrating such materials into devices utilizing the three different readout mechanisms described above will be introduced and discussed. Finally, applications beyond the pure memory operation will be illustrated. An outlook towards future developments will conclude the talk.
References:
[1] T. Schenk, M. Pešić, S. Slesazeck, U. Schroeder and T. Mikolajick, Memory technology—a primer for material scientists, Rep. Prog. Phys. 83, 086501 (2020)
[2] T. Mikolajick, M. H. Park, L. Begon‐Lours, and S. Slesazeck, From Ferroelectric Material Optimization to Neuromorphic Devices, Adv. Mater. 35, 2206042 (2023)
[3] T.S. Böscke, J. Müller, D. Bräuhaus, U. Schröder, and U. Böttger, Ferroelectricity in hafnium oxide thin films, Appl. Phys. Lett. 99, 102903 (2011)
[4] S. Fichtner, N. Wolff, F. Lofink, L. Kienle and B. Wagner, AlScN: A III-V semiconductor based ferroelectric, Journal of Applied Physics 125, 114103 (2019)
[5] U. Schroeder, M. H. Park, T. Mikolajick, and C. S. Hwang, The fundamentals and applications of ferroelectric HfO2, Nature Reviews Materials volume 7, pages653–669 (2022)
About the Speaker
Thomas Mikolajick received the Dipl.-Ing. and the Dr.-Ing. In electrical engineering in 1990 and 1996 both from the University Erlangen-Nuremberg. From 1996 till 2006 he was in semiconductor industry (Siemens Semiconductor, Infineon, Qimonda) developing CMOS processes and memory devices with a strong focus on nonvolatile memories. In 2006 he was appointed professor for material science of electron devices at TU Bergakademie Freiberg. Since 2009 he is a professor for nanoelectronics at TU Dresden and in parallel the scientific director of NaMLab GmbH. He is author or co-author of more than 500 publications (current h-index of 90 according to google scholar) and inventor or co-inventor in more than 50 patent families. He is listed as a highly cited researcher in the 2022 and 2023 editions of Clarivate´s highly cited researchers list. In 2018 he served as the general chair of the IEEE ESSDERC/ESSCIRC conference in Dresden and in 2020/21/22 as the local chair and in 2023 as the general chair of the IEEE International Memory Workshop (IMW). From 2010 till 2019 he was the speaker of the BMBF leading edge cluster “Cool Silicon”. Currently he is one of the speakers of the center for advancing electronics Dresden (cfaed). Since 2019 he is also the speaker of the BMBF ForLab consortium. He is a member of IEEE since 1999 and received the senior membership status in 2009. Since 2023 he is an IEEE Fellow for “Contributions to Nonvolatile Memory”.