Seong-Woo Kim1
Orbray Co, Ltd1
Diamond semiconductors, owing to their superior properties compared to SiC and GaN, can be used to develop high-end applications, such as power devices, high frequency devices, quantum devices, and sensors. However, the inch-scaled diamond wafer is essential. In this study, Two-inch-diameter high-quality diamond (001) layers were grown on sapphire (11-20) A-plane misoriented substrate. Step-flow growth in diamond is realized thanks to misoriented substrate, and releases tensile strain in diamond layer. Consequently, even if microneedle technique<sup> [1]</sup> is not used, without breakage, diamond layer naturally was delaminated from the sapphire substrate. The FWHM of (004) and (311) X-ray rocking curves of the diamond layer grown on sapphire substrate misoriented by 7° towards [1-100] direction were 75 and 140 arcsec, respectively, the lowest ever.<br/><br/>In this study, results on 3 types of high-end applications will be discussed. One of them is the world largest diamond detector with the dimensions of 20 mm ' 20 mm ' 0.5 mm was fabricated from a 30 mm ' 30 mm heteroepitaxial diamond wafer. The device demonstrated a nuclide discrimination capability for 133Ba, 137Cs and 60Co based on the pulse-height difference. The electrode was used as a cathode to apply -500 V bias voltage. The anode on another side was connected to a charge sensitive preamplifier. The anode was maintained at ground potential. The output signal from the preamplifier was acquired with a digitizer. A digital trapezoidal filter was applied to the waveforms to obtain pulse height spectra.<br/><br/>[1] S.-W. Kim et al., Appl. Phys. Lett. 117, 202102 (2020).