We present the results for crystalline growth of praseodymium oxide on Si as a potential high-K dielectric with promising electrical properties. All layer growth experiments were performed using solid source molecular beam epitaxy. The initial stages of growth were studied by scanning tunneling microscopy. On Si(0 0 1) surfaces, crystalline Pr2O3 grows as (1 1 0)-domains, with two orthogonal in-plane orientations. Epitaxial silicon overgrowth seems to be impossible. We obtain perfect epitaxial growth on Si(1 1 1). These layers can also be overgrown epitaxially with silicon. (C) 2002 Elsevier Science B.V. All rights reserved.