Metrology of scanning microwave microscopy applied to transport measurement for semiconductors

This thesis is focuses on the establishement of a metrology for measurement of electrical properties at the sub-micrometric scale. The Scanning Microwave Microscopy (SMM) satisfies those conditions by allowing for measurement of electrical impedance, permittivity and dopant concentration. It is an Atomic Force Microscope (AFM) interface to a Vector Network Analyser (VNA). If the metrology associated with VNA measurement is well established, it is not the case for the one associated with SMM measurements. A calibrated VNA can access the electrical properties of a sample from the reflection parameter measurement. For a SMM setup, the most commonly used method is a modified Short-Open-Load calibration using three impedance on a calibration sample.

One of the key result of this thesis is the preparation of a comprehensive uncertainty budget associated with the impedance measurement performed by the SMM. To this end, the capacitors of the reference sample were fully characterized with uncertainty below 2.8 %. Using this uncertainty budget, a second version of the calibration standard was proposed and characterized with associated uncertainty below 1.9 %. The uncertainty associated with capacitance measurement by the calibrated SMM is found below 3 %.

The extraction of dielectric constant of piezoelectric samples with uncertainty below 6.9 % is presented as an application case for this method. The uncertainty due to relative humidity (RH) on the SMM calibration was studied both empirically and by numerical simulation. The RH impacts the calibration at the 0.4 % level for the smallest capacitance studies (0.3 fF) and is negligible for capacitance above 4 fF. Finally, dC/dz curves were acquire by electrostatic force microscopy (EFM) above a known dielectric as an alternative method for cantilever’s spring constant measurement.

scanning microwave microscopy, SMM, atomic force microscope, AFM, electrical properties, measurement at the sub-micrometric scale, electrical metrology, capacitance reference structure

Full document (EN) : TEL-04748080