Automated electron channeling-based defect metrology for beyond-Si semiconductors

Nanoelectronic and photonic devices such as transistors, lasers, light emitting diodes (LED) and optical sensors plays an important role in our daily life. Such devices are mainly based on the heterogeneous structures of (Si)Ge alloys, III-V (e.g. GaAs, InGaAs) and III-N (e.g. GaN) compounds integrated on Si substrates. During the epitaxial growth, the lattice and thermal mismatch between epitaxial layers and the underlying substrate can lead to high strain/stress. This can further generate different types of crystalline defects (e.g. threading dislocations, stacking faults) during the plastic relaxation. Such defects can strongly influence the surface/interface morphologies, electrical/optical properties and thus the performance of related devices. As a result, it is important to detect and monitor such defects. Nowadays the state-of-art hetero-epitaxy layer systems can reach a low defect density levels (<10⁵/cm²), which significantly adds the difficulty during defect characterization. As a fast, reliable and non-destructive technique, electron channeling contrast imaging (ECCI) is promising to investigate large areas thereby facilitating a lower detection limit. To reduce the measurement time, automation in ECCI attracts more and more interest.

The goal of this internship is to find out the optimized imaging conditions and to apply such tool conditions for automated ECCI. Both manul and automated ECCI will be done for comparison. The student should have good knowledge in programming (Python) or have good knowledge in C, C++, or matlab programming and be willing to learn Python. The student should know or be willing to learn crystallography, scanning electron microscopy (SEM) and semiconductor characterizations.

For this topic, the student will mainly work in the SEM lab and carry out the required experimental steps. The student will characterize the imec-internal samples to assess the automated ECCI. The student will be part of imec’s materials and component and analysis group.