Vanadium dioxide (VO 2 ) has the interesting feature that it undergoes a reversible semiconductor-metal transition (SMT) when the temperature is varied near its transition temperature at 68°C. 1 The variation in optical constants makes VO 2 useful as a coating material for e.g. thermochromic windows, 2 while the associated change in resistivity could be interesting for applications in microelectronics, e.g. for resistive switches and memories. Due to aggressive scaling and increasing integration complexity, atomic layer deposition (ALD) is gaining importance for depositing oxides in microelectronics. However, attempts to deposit VO 2 by ALD result in most cases in the undesirable V 2 O 5 .In the present work, we demonstrate the growth of VO 2 by using Tetrakis[EthylMethylAmino]Vanadium and ozone in an ALD process at only 150°C. XPS reveals a 4+ oxidation state for the vanadium, related to VO 2 . Films deposited on SiO 2 are amorphous, but during a thermal treatment in inert gas at 450°C VO 2 (R) is formed as the first and only crystalline phase. The semiconductor-metal transition has been observed both with in-situ X-ray diffraction and resistivity measurements. Near a temperature of 67°C, the crystal structure changes from VO 2 (M1) below the transition temperature to VO 2 (R) above with a hysteresis of 12°C. Correlated to this phase change, the resistivity varies over more than 2 orders of magnitude. This work has been accepted for publication in Applied Physics Letters. The inset shows the in-situ XRD measurement from which the peak intensity was integrated.

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VO2 and V2O3 thin films were prepared during in situ XRD investigation by oxidation and reduction of V and V2O5. Films show up to 5 orders of magnitude resistance switching.

We studied the solid-phase reaction between a thin Ni film and a single crystal Ge(001) or Ge(111) substrate during a ramp anneal. The phase formation sequence was determined using in situ X-ray diffraction and in situ Rutherford backscattering spectrometry (RBS), while the nature and the texture of the phases were studied using X-ray pole figures and transmission electron microscopy. The phase sequence is characterized by the formation of a single transient phase before NiGe forms as the final and stable phase. X-ray pole figures were used to unambiguously identify the transient phase as the-phase, a non-stoichiometric Ni-rich germanide with a hexagonal crystal structure that can exist for Ge concentrations between 34% and 48% and which forms with a different epitaxial texture on both substrate orientations. The complementary information gained from both RBS and X-ray pole figure measurements revealed a simultaneous growth of both the-phase and NiGe over a small temperature window on both substrate orientations. V