Prof. De Salvador's research activities are primarily focused on semiconductor materials, with a particular emphasis on studying doping processes and diffusion mechanisms in silicon and germanium. He employs experimental methodologies based on fundamental analytical and processing tools available at the Padua Physics Department, including:

Secondary Ion Mass Spectrometry (SIMS) for analyzing the chemical profile of dopants within the materials. High-Resolution X-ray Diffraction (HRXRD) to investigate structural defects and lattice deformation.Van der Pauw-Hall measurements to quantify dopant activation and carrier mobilities.
Dr. Salvador is an expert in these methods and, notably, oversees the HRXRD and van der Pauw-Hall laboratories. Additionally, he coordinates the RBS-NRA-channeling facility installed at AN2000 and CN accelerators of LNL.

In terms of processing, Dr. Salvador specializes in physical deposition methods such as sputtering and evaporation, as well as laser processing.

His expertise includes the simulation of experimental data using continuum differential equation computing, which facilitates the development and calibration of predictive physical models.

Furthermore, Dr. Salvador is deeply involved in relativistic channeling research, which explores the coherent interaction of crystals with accelerated beam particles. This impactful research has been conducted in collaboration with INFN of Ferrara for several years under the CNS5 projects, with recent publications showcasing data collected at CN and AN LNL accelerators. His expertise extends to micromachining of germanium, crystal characterization, and precise alignment using high-precision goniometers.

In recent years, Dr. Salvador contributed to the GAMMA experiment of INFN, focusing on studying repair processes and innovative methods for contact production in HPGe gamma detectors. This effort led to the PRONG and N3G projects within CSN5, yielding significant progress in creating junctions in HPGe detectors via the Pulsed Laser Melting technique. The goal is to utilize sputtering deposition and laser annealing processes to create stable and highly segmented contacts on HPGe planar detectors. Technical development for implementing this technology in Coaxial detectors has been undertaken in the framework of the N3G Call CSN5 project by LNL, with support from the FE unit for segmentation development, MI for innovative electronics, and PD for advanced detector testing under irradiation.

Dr. Salvador holds the role of national coordinator for N3G and is a co-author of the PCT patent WO2021214028A1, titled "P+ OR N+ TYPE DOPING PROCESS FOR SEMICONDUCTORS," which pertains to laser doping of semiconductors by means of sputtered films and has been extended in the US and EPO.

With approximately 170 peer-reviewed articles to his name, he also serves as a referee for Physical Review Letters. He obtained national scientific qualification for the first-level professorship in the experimental material physics sector in July 2017.

Laser doping process for the development of gamma imaging devices

The creation of images of gamma sources is a rapidly expanding research sector thanks to the numerous applications in the medical, astrophysical and safety fields. The hyperpure germanium is among others the most interesting semiconductors for these applications, thanks to the high energy resolution (low gap) and the large volumes of interaction. However, the processes for obtaining segmented devices (with electrically separated electrical contacts) are not very efficient, mainly because the standard processes of microelectronics can degenerate the purity of the material (1 doping impurity over 10 ^ 12 atoms). The use of pulsed lasers to produce contact doping is an extremely promising technique thanks to the localized and short heating induced in the material. The aim of the thesis is to produce and characterize segmented hyperpure germanium detectors by laser technique. The student will follow the whole process from the ideation through simulations, to the realization of contacts through lithographic and laser processes, to the electronic characterization of the contacts and of the final device performances. The activity will be carried out in the DFA and Legnaro laboratories and represents a complete training opportunity in the world of semiconductor devices.