Conference Agenda

The increasing reliance on efficient power-switching technologies necessitates advancements in semiconductor materials to reduce energy losses. This study investigates the potential of beta-gallium oxide (β-Ga₂O₃) for power electronic converters, leveraging its ultra-wide bandgap and high breakdown field strength. Homoepitaxial β-Ga₂O₃ films up to 4µm thick were grown via metal-organic vapor phase epitaxy (MOVPE) on (100) 4° off-oriented substrates. The research explores growth mechanisms, including step-flow growth optimization, and addresses challenges in vertical device architectures requiring thick, low-doped layers. The growth approach used in this work enabled for the (100) orientation record mobilities above 160 cm²/Vs and improved growth rates, enhancing the material’s viability for next-generation power electronics.

Monoclinic β-Ga₂O₃ is an ultra-wide bandgap semiconductor with a pronounced anisotropy in its optical, electronic, and thermal properties, emerging from the coexistence of two different Ga coordination environments. In this work, we study the anisotropic optical response of mechanically exfoliated (100)-oriented β-Ga₂O₃ nanomembranes using synchrotron radiation-based techniques. The correlative study of polarization-resolved X-ray excited optical luminescence (XEOL) and X-ray absorption near edge structure (XANES) spectroscopy was used to investigate the orientation-dependent luminescence and absorption, as well as the site-specific contribution of Ga ions to the luminescence process. These oriented-dependent optical properties reveal its potential for a wide range of advanced applications.

In this work, the molecular beam epitaxy with ammonia source (NH3-MBE) has been developed to grow AlScN/GaN high electron mobility transistor (HEMT) heterostructures on sapphire and silicon substrates. The capping of AlScN surface with AlN and or GaN thin layers has been studied as well as the insertion of an AlN interlayer between the barrier and the GaN channel.

A three-layered diamond/AlN/diamond structure has been grown. Firstly, the AlN deposition on free-standing boron-doped diamond (BDD) has been optimized by using two different temperatures (400 ℃ and 600 ℃) to obtain a c-axis oriented film. Once the deposition temperature has been analysed, the effect of different deposition times on the film crystallinity has been also studied. Finally, a BDD layer has been grown on top of the AlN/diamond heterostructure to obtain the three-layered structure.

We present a novel inter-die Cu/diamond microbump bonding to reduce inter-die thermal resistance in 3D heterogeneous packaging systems. The fabrication process began with the chemical vapour deposition (CVD) of a 8 um-thick polycrystalline diamond film on Si. An array of cylindrical vias was etched through the diamond surface using oxygen plasma. Cu/Sn microbumps were fabricated within the etched volume using electroplating. Finally, two diamond-coated dies were bonded through thermocompression hybrid flip-chip bonding.