SKM 2021 – scientific programme
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 4: Focus Session III: Diamond
KFM 4.1: Invited Talk
Tuesday, September 28, 2021, 14:15–14:45, H2
Single crystal diamond growth by chemical vapor deposition for high-end applications: Recent trends and state of the art — •Matthias Schreck and Theodor Grünwald — Institut für Physik, Universität Augsburg, 86135 Augsburg, GERMANY
In order to profit from diamond s unique material properties for demanding device applications, wafer size single crystals are needed. Currently, two alternative concepts based on chemical vapor deposition (CVD) are being explored. Crystals grown by homoepitaxy on seeds from the high pressure method excel in structural quality but suffer from severe size limitations. In contrast, heteroepitaxy on iridium using the multilayer substrate Ir/YSZ/Si(001) has recently provided the first real wafer with a diameter of 92 mm (155 carat). While dislocation densities of 7 × 106 cm−2 and mosaic spread values of 0.03∘ (polar) and 0.05∘ (azimuthal) document significant progress, the defect structure is still inferior to homoepitaxial diamond. After reviewing the current state of the art, recent and new attempts for further reduction of the dislocation densities are described. These comprise different variants of epitaxial lateral overgrowth (ELO) and metal assisted termination (MAT). Next, the electronic properties of threading dislocations in heteroepitaxial diamond have been investigated. Experimentally derived lifetime values enable estimations of capture cross sections for electrons and holes. In the final part, a new smart-cut technique is presented that facilitates a duplication of large area diamond wafers removing the need for new nucleation and elaborate dislocation density reduction procedures to be applied for every new wafer.