Metrology device and method

A method for determining metrological characteristics of a sample with conductive features embedded in a layer of a material or a combination of materials having a conductivity different from that of the conductive features, the method comprising:

• carrying the sample;
• displacing a probe relative to the sample, along a surface of the sample, the probe having a diamond tip with one or more nitrogen-vacancy centers;
• irradiating the diamond tip with photon radiation to excite the diamond tip to emit fluorescent light;
• optically sensing the diamond tip and providing a sense signal indicative of an intensity of fluorescent light emitted by the diamond tip;
• processing the sense signal to compute at least one characteristic of a feature present in the sample;
• subjecting, during the irradiating, the sample to a source magnetic field with at least a first frequency and a second frequency, which are mutually different;
• and
• analyzing the sensed signals for each of the at least the first frequency and the second frequency to identify a material present in the sample near the diamond tip.