ELECTRICAL SPM CHARACTERIZATION AND ANALYSIS OF IGZO FOR LOGIC AND MEMORY APPLICATIONS

InGaZnO (IGZO) is a quaternary, n-type semiconducting oxide under extensive study due to its promising mechanical and electrical properties. Initially discovered and studied in the crystalline form for Thin Film Transistor (TFT) application, more recently the amorphous phase has become a good candidate for a wider spectrum of electronic devices ranging from back-end-of-line compatible logic (due to its low thermal budget) to selectors for emerging memory architectures. However, several challenges are associated with use, tuning and control of IGZO properties. Among others, controlling the film quality and stoichiometry during the manufacturing process can be complicated due to the large variety of IGZO phases. In addition, the screening of multiple deposition conditions can be expensive due to device fabrication, testing and debugging. Therefore, in this thesis we have explored conductive atomic force microscopy (C-AFM) as a possible solution to establish a framework of analysis that enables the fast assessment of material properties of IGZO on blanket thin films. The work describes the methodology and results obtained during a six-month internship period spent at imec (Belgium). First, we report on the use of C-AFM to measure electrical properties of insulating thin films, with nanometric lateral resolution. This is combined with the analysis of multiple types of IGZO films, thus correlating material properties with deposition conditions. Finally, we compare different IGZO phases with emphasis on materials with application in transistor and selectors for emerging memory devices.