Material and interface quality analysis by surface harmonic generation (SHG)

Laboratory : IMEP-LaHC, Grenoble-INP

Contact: Irina Ionica

Key words:
second harmonic generation, thin layers optical properties, modeling

Context:
This topic is in the context of research on novel characterization methods of ultra-thin films and interface quality for applications in micro, nanoelectronics, photovoltaics, photonics, etc.
A key element today is to propose and develop innovative characterization methods that do not need any physical contact, therefore avoiding any damage of the advanced ultra-thin substrates.
A very promising technique was recently proposed: the second harmonic generation (SHG)1. A laser emitting at the fundamental frequency can induce polarisation of the material. The intensity measured at double frequency is proportional to the second order non-linear polarisation of the material and is named the second harmonic. An additional SHG contribution can appear due to the electric field induced second harmonic (EFISH). The interest in the SHG resides in its sensitivity to material and interfaces quality and particularly to the electric field at semiconductor – dielectric interfaces, which is related to presence of charges (fixed, interface states, traps, etc).

Objective:
An innovative SHG equipment, unique in Europe, very recently developed and fabricated by FemtoMetrix (USA) was recently installed at IMEP-LAHC.
The first objective will consist in qualifying the measurement tool, using different samples (dielectrics on semiconductors, silicon-on-insulators…).
Based on these results, the second objective is to validate and extend models for SHG, for the extraction of material quality parameters such as the density of interface states.

Requested competences:
This topic is an interdisciplinary topic, in the fields of optics, micro-electronics, and material science. The candidate must have a very good background in optics,
semiconductor physics, microelectronics.

Collaborations:
This work is done in the context of different collaborations that the team has with groups (academic and industrial) involved in the material fabrication (INSA Lyon, SOITEC, CEA-LETI). She/he will also be in contact with the tool fabricant in California. Therefore the student will be in a stimulating professional environment, in touch with both academic and industrial research actors which should be very beneficial for hers/his future career.

The internship topic is going to be proposed for a PhD thesis, starting from October 2018.

1 B. Jun, et al., IEEE Transactions on Nuclear Science, vol 51, 3231 (2004).
M.L. Alles et al, IEEE Transactions on Semiconductor Manufacturing, vol. 20, 107 (2007

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