Study of sub-surface grains at the poly-mono interface of SmartCut substrates

We propose to perform Laue µdiffraction on SiC substrate heterostructures fabricated by means of the SmartCut process, to extract a map of the grains in the near-surface region with a top monocrystalline film. This information was previously impossible to recover from experiments using conventional sCMOS detectors due to the complexity of the diffraction patterns (Figure 1a). This complexity arises from high-energy photons that penetrate too deeply into the samples, mixing signals from numerous grains located far below the interface. However, the brand new EIGER2 X CdTe 4M detector at BM32 enables it to restrict detection to a low-energy photon band [1]. This suppresses deep-grain contributions, simplifies the Laue patterns (reducing the number of spots per grain, cutting the harmonics), and biases the measurement into probing only the grains closest to the interface of interest.