Vacuum Scanning Microwave Microscopy for quantitative characterization of sub-10 nm and atto-Farad scale capacitors and memories

• Applicant: Professor Dr.-Ing. Sergej Fatikow
• Subject Area: Measurement Systems ; Automation, Mechatronics, Control Systems, Intelligent Technical Systems, Robotics
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 258650972

As device scaling will continue below 20 nm and novel nanodevices already appear on the market, accurate characterization and detailed understanding of their electronic structure is essential, yet challenging. In particular, nanocapacitors and tunnel barriers, that are building blocks in most memories, are extremely difficult to characterize due to capacitances in the atto-Farad range. Recently developed Scanning Microwave Microscopes (SMMs) are almost showing such abilities but their operation, only limited to air or nitrogen environment, lead to difficult quantitative characterization due to well-known parasitic water meniscus contribution. Other Scanning Probe Microscopes (Atomic Force Microscopes, Kelvin Force Microscope, Scanning Tunneling Microscopes and other), have been proposed with vacuum or ultra-high vacuum versions to remove this parasitic effect, but also to protect sensitive devices.In this project, we propose to build, for the first time, a SMM under vacuum (VACSMM) that will combine nanoscale contact, imaging, SEM observation and FIB refining of AFM tips, reduced electrical parasitics, DC and RF measurements. It will be equipped with an interferometer allowing aF capacitance sensitivity. Sub-10 nm capacitors and memories will be fabricated with an on-chip calibration kit to achieve a quantitative electronic study on these devices. In particular, statistical studies will be performed on the capacitance, conductance and switching rates (for OxRAMs memories) and models/theory will be proposed (finite element modeling, analytical models for S parameters, physics of atomic switches).The fabricated VACSMM will coexist inside a SEM, automation methods will be developed as a perspective to make this apparatus a possible industrial tool for nanoscale capacitors and memory characterization before top electrode fabrication. This German-French joint project is a great opportunity to combine complementary expertise in nanodevices fabrication and SMM (French partner) and self-made Atomic Force Microscope/SEM under vacuum including software and robotic automation tools (German partner).

• DFG Programme: Research Grants
• International Connection: France
• Participating Person: Privatdozent Didier Theron, Ph.D.