Surface passivation for III-V materials integrated on silicon: analysis of surface recombination by second harmonic generation (SHG) and C-V measurements

Surface passivation for III-V materials integrated on silicon: analysis of surface recombination by second harmonic generation (SHG) and C-V measurements

Scientific context:

When integrating III-V materials onto silicon platforms, surface recombination is one of the main obstacles to the performance of future optoelectronic devices.
III-V surfaces and interfaces have a high density of electronic states that trap carriers, limiting the efficiency of integrated photodetectors and emitters.
Reducing these recombinations requires effective passivation processes adapted to III-V/Si heterostructures. Their evaluation relies on techniques that are sensitive to surface state: second harmonic generation (SHG), which is well suited for probing the quality of surfaces and interfaces, and C-V measurements on capacitive structures, which allow the density of surface states to be quantified.

Intership:

The internship focuses on the study of surface recombination and passivation optimisation. The objectives are:

• To develop and apply different passivation processes (chemical and/or dielectric) specifically adapted to III-V surfaces.
• Evaluate the effectiveness of treatments by analysing the evolution of surface recombination by SHG and extracting the surface state density and interface charges by C–V.
• Correlate SHG signatures and electrical parameters in order to identify the most effective treatments.
• Propose a technological process for optimal passivation of III-V materials on silicon.
   

Planned work:

• Implementation of passivation processes (chemical treatments, deposits, annealing).
• SHG characterisation of passivated surfaces and interfaces.
• Fabrication/measurement of capacitances and extraction of C–V parameters.
• Cross-analysis of SHG/CV to understand surface recombination mechanisms.
• Synthesis of results and recommendations for passivation.

Required profile:

• Master's degree or engineering school graduate with an interest in:
  semiconductors,
• characterisation (electrical and non-linear optical) of materials,
• clean room experimentation.