Growth and characterization of monocrystalline tungsten substrates

High-purity tungsten single crystals of different crystallographic orientat ions were prepared by electron beam floating zone melting as well as by a s train-annealing technique. The substructure of these substrates was examine d by SEM, optical microscopy and X-ray diffraction methods. Samples were pr epared with different crystallographic planes and with substructures free f rom small-angle boundaries. The samples had excellent structure parameters, as deduced from the full-width at half-maximum of the rocking curves which was less than 0.1 degrees for the substrates prepared by strain annealing. The substrates were subsequently cleaned in UHV using a newly designed com pact electron beam gun for heating to 2500 degrees C. The surface cleaning procedures were studied using AES, LEIS and LEED. Clean and well-ordered su rfaces were obtained. (C) 1999 Elsevier Science Ltd. All rights reserved.