SPREADING RESISTANCE PROFILING

The Spreading Resistance Profiling (SRP) technique is an established methodology that is in use in both industry and research for measuring resistance profiles and, following calibration, the density profiles of active carriers in state-of-the-art semiconductor geometries. Two metallic probes, between which a controlled potential (small V_SRP=5 mV, for Si or Ge) is applied, are used to quantify the charge carrier distributions as a function of depth. Depth information is obtained by stepping down the probes along a bevelled surface of the sample. During the measurement a resistance profile is acquired, which is computed and converted into resistivity and carrier concentration by means of calibration curves (mobility parameters of monocrystalline materials). A particular algorithm is also applied which corrects for sampling volume effects in case of ultra-shallow profiles.

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Catania

CNR-IMM@CT

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Also consider

Ultrafast spectroscopy (or Pump-probe spectroscopy) is a technique used to study the dynamics of excited states in various materials, such as molecules, semiconductors, and solids.

It involves the use of two laser pulses. The first laser pulse, the "pump," excites the sample, elevating electrons from the ground state to an excited state. This initiation creates a non-equilibrium condition in the sample. After a controlled delay, a second laser pulse, the "probe," is sent through the sample. The probe pulse interrogates the sample to gather information about the transient states and the evolution of the excited states over time.

By varying the delay time between the pump and probe pulses, researchers can create a time-resolved picture of the dynamic processes occurring in the material. This time resolution can be on the order of femtoseconds (10^-15 seconds), allowing scientists to observe ultrafast phenomena.

These techniques provide insights into ultrafast processes, such as electronic transitions, high-order harmonics generation, molecular vibrations, and energy transfer mechanisms, that occur on very short time scales. It helps in understanding the fundamental properties of materials, such as the relaxation times of excited states, carrier dynamics in semiconductors, topological effects and the mechanisms of photochemical reactions.

Other possible studies can cover the world of solar cells, light-emitting devices, and photocatalysts, where understanding the dynamics of excited states is essential for improving efficiency and performance. Moreover, in biophysics and biochemistry, pump-probe spectroscopy can be used to investigate the dynamics of biomolecules, such as the folding and unfolding of proteins, photosynthesis mechanisms, and the behavior of molecular motors.

Ultrafast-Spectroscopy

Advanced Characterization and Fine Analysis