Ultra-thin high-quality silicon nitride films on Si(111)

¹ Institute of Solid State Physics, University of Bremen - Postfach 330440, D–28334 Bremen, Germany, EU
² ELETTRA Synchrotron Light Source - Strada Statale 14, km 163.5, 34149 Basovizza, Trieste, Italy, EU
³ School of Physics and Astronomy, University of Nottingham - Nottingham NG7 2RD, UK, EU (b)
⁴ NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore - Piazza San Silvestro 12, 56127 Pisa, Italy, EU

^a falta@ifp.uni-bremen.de

Received: 14 December 2010
Accepted: 9 March 2011

Abstract

Ultra-thin silicon nitride films grown by exposure of Si(111) substrates to a flux of atomic nitrogen at temperatures between 700 ^°C and 1050 ^°C have been investigated by means of X-ray spectromicroscopy, atomic force microscopy, X-ray reflectivity, and X-ray photoemission spectroscopy. The films show a Si₃N₄ stoichiometry. For reactive nitride growth at temperatures below 800 ^°C, a smooth surface and interface morphology is found. Higher temperatures lead to the formation of rough films with holes and grooves of increasing size, approaching a lateral size of several hundred nanometers for growth temperatures above 900 ^°C. Nonetheless, X-ray spectromicroscopy shows that the bottom of the holes consists of Si₃N₄.