PI (Physik Instrumente) published an interesting technote about using scanning probe microscopy with piezo stages and capacitive nanometrology sensors to improve nano-indentation and materials testing systems. The NanoTest from Micro Materials is ideal for use with a wide range of materials because it can apply forces of between 30 nN and 500 mN depending on the operating mode, and it can measure penetration depths of between 0.1 nm and 50 ìm. The task is carried out by a high-resolution capacitive sensor, the PISeca sensor from PI.
Scratches in a hard nano-composite layer on silicon before (left) and after leveling
Nanoindentation is derived from the classical hardness test but is carried out on a much smaller scale. It can be used to determine the hardness of thin layers as well as material properties such as elasticity, stiffness, plasticity, and tensile strength, or fracture toughness of small objects and microsystems in fields such as biotechnology. These measurements involve applying a small force to a sample using a sharp probe and measuring the resultant penetration depth. The measured value is used to calculate the contact area and hence the particular property of the sample material. Both the method of force application and the geometry of the indentation tip can be adjusted to suit the particular application.