This non‐contact high‐k monitoring technique is based on a differential quasistatic C‐V that is generated using time‐resolved metrology combining corona charging and contact potential difference (CPD) measurements. The technique incorporates transconductance corrections that enable measurements in the high field range (10MV/cm) required for extraction of large dielectric capacitance corresponding to ultra‐low equivalent electrical oxide thickness (EOT) down to the sub‐nanometer range. It also provides a means for monitoring the flat band voltage, VFB, the interface trap spectra, DIT, and the total dielectric charge, dQTOT. This technique is seen as a replacement for not only MOS C‐V measurements but also for mercury‐probe C‐V. EOT measurement by the differential corona C‐V has a major advantage over optical methods because it is not affected by water adsorption and molecular airborne contamination, MAC. These effects have been a problem for optical metrology of ultra‐thin dielectrics. The presented results illustrate the application of the technique to state of the art gate dielectrics, including Si‐O‐N and HfO2. © 2003 American Institute of Physics