2. Capacity measurement

2.1 Introduction

Capacitance measurement is used in many fields relating to sensors (pressure, displacement...), but also for many applications linked to memories and other electronic devices. These sectors of activity are also suffering the consequences of extreme miniaturization, driven by the need to develop the least invasive sensors possible for bio-medical applications (in vivo measurements, monitoring, etc.). Measurement techniques must therefore once again evolve towards largely sub-micron spatial resolutions.

However, electrical capacitance is by definition an extensive quantity, proportional to the surface area of the opposing capacitor plates. For this reason, capacitance measurements involving an AFM tip with a very small surface area have to be...