1 May 2007 NIM Semi-transparent SiC Schottky Diodes for X-ray spectroscopy J.E. Lees* 1 , D.J. Bassford 1 , G.W. Fraser 1 , A.B. Horsfall 2 , K.V. Vassilevski 2 , N.G. Wright 2 and A. Owens 3 Abstract We describe a novel SiC Schottky diode architecture. The semi-transparent SiC Schottky diode has an “ultra-thin” (18 nm Ni/Ti) Schottky contact, a gold annular overlayer and a gold corner-contact pad. We show that the new architecture exhibits the same essential characteristics as a more conventional ‘thick-contact’ Schottky diode (≥ 100nm). Such diodes will have a higher efficiency for low energy (< 5 keV) X-rays than that of conventional structures combined with minimal self-fluorescence from the electrode materials. We present X-ray spectra from 55 Fe, 109 Cd and 241 Am radioactive sources that show these diodes can be used for spectroscopy with promising energy resolution (1.47 keV FWHM at 22 keV) at room temperature (23ºC). The reduction in contact thickness, however, does reduce the barrier height of the new diodes in comparison to those fabricated using the conventional process, and requires a trade-off between the low energy detection threshold and the noise in the detector. PACS: 07.85.Fv, 29.40.Wk Keywords: X-ray detection, Silicon Carbide, Schottky contact *Corresponding author: +44 116 252 5519, E-mail address lee@star.le.ac.uk 1 Space Research Centre, Department of Physics and Astronomy, Michael Atiyah Building, University of Leicester, Leicester, LE1 7RH, UK 2 Semiconductor Technology Group, School of Electrical, Electronic and Computer Engineering, Merz Court, University of Newcastle, Newcastle, NE1 7RU, UK 3 Office of Science Payload and Advanced Concepts, European Space Agency ESTEC SCI-A, Postbus 299, 2200AG Noordwijk, The Netherlands 1