First Results of CVD-Diamond Detectors Grown on Large Iridium Substrates

A promising course for large-area ‘quasi’ single-crystal CVD diamond (scCVDD) is the heteroepitaxial growth on the multilayer structure Ir/YSZ/Si(001) [1] as developed at the University of Augsburg on 4inch wafers. Key issue is the similarity of the lattice constants of diamond (dDia = 3.567 Å) and Iridium (dIr = 3.834 Å). Figure 1 shows characterization results of two Diamond-on-Iridium (DoI) samples compared to commercial scCVDD and polycrystalline CVD-diamond (pcCVDD) detectors [2]. DoI549a (topand central-right data) is a polished freestanding film of 230μm thickness, where a 30μm layer has been removed from the nucleation side. The thickness of DoI724b (bottom left and right data) was optimized for Transient-Current Technique (TCT) measurements with Am-α-particles: an iridium mesh was added in the depth of the α-range providing dD ≈ 12μm.