Growth of ZnSe and ZnS films on Si(111) substrates with a nitrogen surfacetreatment

We have investigated the effects of substrate surface irradiation with nitr ogen plasma prior to growth on the initial stages of the heteroepitaxy of Z nSe on Si(111). The reflection high-energy electron diffraction (RHEED) pat terns during the pulsed molecular beam epitaxial growth of ZnSe on the N-pl asma-treated Si surface showed very well-defined streaks with a twofold rec onstruction indicating an atomically flat surface. In sharp contrast, durin g the initial stages of the ZnSe growth on untreated Si substrates, spotty RHEED patterns with a diffuse background were observed. A strong evidence o f the two-dimensional ZnSe nucleation obtained on the N-plasma-treated Si s urface was the clear presence of large-amplitude RHEED oscillations. Atomic force microscopy measurements confirmed that we have achieved a substantia l improvement on the ZnSe heteroepitaxy on Si substrates. We show that this novel N-plasma substrate treatment is useful for the growth of other Zn-ch alcogenides compounds on Si substrates. (C) 1999 American Vacuum Society. [ S0734-211X(99)03903-7].