Strain mapping in functional GaN/Si and SiGe/Si microelectronic devices

We will employ Scanning X-ray Diffraction Microscopy (SXDM) at ID01 to compare the strain distribution in two devices based on epitaxial GaN/Si heterostructures from the ADDMOREPOWER consortium for high-power devices before and after electrical stressing. The samples were precharacterized by electron microscopy to identify spatial regions that become degraded during the stress test. The comparison will allow us to correlate electrical failure with the evolution of the strain landscape.

Moreover, we will measure a region of a Si/SiGe-based 'QuBus' structure where blockade of spin-coherent shuttling was previously observed and is suspected to be linked to the presence of structural defects such as dislocations. SXDM will observe the presence of dislocations in the 8 nm-thick buried Si quantum well layer and quantify the magnitude of their strain fields, which may hinder the shuttling.