27 août 2024
16:00
Louvain-la-Neuve
Auditoire BARB91 – Pl. Sainte-Barbe - - will also take place in video conference
Characterization, modelling and mitigation of substrate-induced effects in RF GaN-on-Si technology by Pieter Cardinael
Modern telecommunication systems are characterized by a high data traffic, imposing stringent requirements on the integrated circuits that handle the radiofrequency signal. For applications where efficiency and large power output at a high operating frequency are desired, the widespread Si-based technology is outperformed by novel semiconductors such as GaN. To reduce the cost of GaN electronics, the integration of a thin GaN film on a cheap Si wafer is seen as a promising approach. However, in contrast with other substrates, GaN-on-Si suffers from parasitic power loss in the semiconducting substrate. As a consequence, the performance of passive and active circuitry is degraded and harmonic distortion is generated.
The objectives of this thesis are to understand the physical origin of substrate-induced effects in GaN-on-Si, to quantify their impact on the circuit performance and to mitigate them.
To that aim, we employ and develop electrical characterization techniques, physics-based simulation methods and modelling approaches at every level of the complex material stack. We investigate the contributions of the Si wafer, its interface with the AlN nucleation layer and the upper carbon-doped buffer layers. Backed by the physical understanding, we introduce process guidelines to significantly improve the substrate performance of GaN-on-Si. The analysis of two critical circuits blocks further demonstrates the importance of substrate engineering. Finally, we assess the environmental impact of GaN-on-Si compared to other technologies.
Overall, the insights gained from this thesis contribute to the establishment of GaN-on-Si as a competitive technological candidate for highly efficient high-frequency integrated circuits.
Jury’s members:
Prof. Jean-Pierre Raskin (UCLouvain), supervisor
Prof. Laurent Francis (UCLouvain), chairperson
Prof. Dimitri Lederer (UCLouvain), secretary
Prof. Bertrand Parvais (imec, Belgium)
Dr. Sachin Yadav (imec, Belgium)
Dr. Herwig Hahn (AIXTRON SE, Deutscland)
Dr. Cesar Roda Neve (SOITEC, France)
Pay attention:
The public defense of Pieter Cardinael scheduled for Tuesday Augustus 27 at 04:00 p.m. will also take place in the form of a video conference.