Diamond membranes for X-ray masks

Diamond's high optical transparency, high thermal conductivity, low thermal expansion coefficient, and its high Young's modulus favours it over other materials. The deposition of diamond layers was performed utilizing a plasma activated chemical vapor deposition in a substrate temperature range of 800 to 850 degrees C. The optical transparency of diamond membranes at 630 nm, determined by spectral photometry, was found to be about 38% for a 3.6 mu m thick membrane. The surface roughness of diamond layers, measured by an atomic force microscope, is about 50 nm. Further results of diamond mask blanks concerning thickness homogeneity and radiation stability are reported.