Deposition of Niobium Nitride Thin Films from Tert‐Butylamido‐Tris‐(Diethylamido)‐Niobium by a Modified Industrial MOCVD Reactor

Abstract

AbstractNiobium nitride thin films are deposited on 2″ silicon (100) wafers using a modified industrial metal‐organic (MO) CVD reactor of the type AIX‐200RF, starting from tert‐butylamido‐tris‐(diethylamido)‐niobium (TBTDEN) and ammonia. Films of thicknesses 50‐200 nm are deposited at temperatures ranging from 400 °C to 800 °C under reactor pressures of 1 and 5 mbar using various ammonia flow rates, and are characterized by the use of complementary techniques, namely X‐ray diffraction (XRD), scanning electron microscopy (SEM), secondary neutral mass spectrometry (SNMS), Rutherford backscattering spectrometry (RBS), X‐ray photoelectron spectroscopy (XPS), and electrical measurements. Films deposited above 450 °C consist of the cubic δ‐NbN phase, apart from the presence of Nb‐O and Nb‐O‐N species predominantly in the outermost film regions. The lowest specific resistivities, determined by four point probe measurements, are in the range 500–600 µΩ cm. A NbN/SiO2/p‐Si gate stack is fabricated using the grown niobium nitride films. From the capacitance‐voltage (C‐V)‐curves, flat‐band voltages are extracted which, when plotted against SiO2‐insulator thickness, yield a work function of 4.72 eV for as‐deposited films.