Improved Thermal Stability of Ultrathin CoSi2 Layers by Oxygen Annealing

1998 ◽  
Vol 514 ◽  
Author(s):  
R. T. Tung ◽  
S. Ohmi

ABSTRACTThe thermal stability of thin CoSi2 layers is demonstrated to improve with the use of oxygen-containing annealing ambients. Layer agglomeration in epitaxial and polycrystalline CoSi2 layers grown on single crystal Si and polycrystalline CoSi2 layers grown on α-Si was retarded by oxygen annealing. A thin SiO2 layer grown during oxygen anneals which curbs surface diffusion and reduces the rates of kinetic processes is thought to be the primary reason for the improvement in CoSi2 thermal stability.

1993 ◽  
Vol 73 (11) ◽  
pp. 7969-7971 ◽  
Author(s):  
Qixin Guo ◽  
Osamu Kato ◽  
Akira Yoshida

2020 ◽  
Vol 46 (7) ◽  
pp. 9192-9197 ◽  
Author(s):  
Liaoyuan Zhang ◽  
Wenping Geng ◽  
Xi Chen ◽  
Yimeng Li ◽  
Xiaojun Qiao ◽  
...  

1990 ◽  
Vol 182 ◽  
Author(s):  
J. R. Phillips ◽  
P. Revesz ◽  
J. O. Olowolafe ◽  
J. W. Mayer

AbstractThe thermal stability of Co silicide on single crystal and polycrystalline Si has been investigated. Co films were evaporated onto (100) Si and undoped polycrystalline Si and annealed in vacuum. Resulting silicide films were examined using Rutherford backscattering spectroscopy, scanning electron microscopy, electron—induced x—ray spectroscopy, and sheet resistivity measurements. We find that CoSi2 on single crystal (100) Si remains stable through 1000ºC. In contact with undoped polycrystalline Si, intermixing begins at temperatures as low as 650ºC for 30min annealing. The Co silicide and Si layers are intermixed after 750ºC 30min annealing, giving islands of Si surrounded by silicide material, with both components extending from the surface down to the underlying oxide layer. The behavior of CoSi2 contrasts with results reported for TiSi2 which agglomerates on single crystal Si around 900ºC but is stable on polycrystalline silicon as high as 800ºC. Resistivity measurements show that the Co silicide remained interconnected despite massive incursion by Si into the silicide layer.


2002 ◽  
Vol 744 ◽  
Author(s):  
S. O. Kucheyev ◽  
C. Jagadish ◽  
J. S. Williams ◽  
P. N. K. Deenapanray ◽  
Mitsuaki Yano ◽  
...  

ABSTRACTThe formation of highly resistive films of single-crystal ZnO as a result of irradiation with MeV Li, O, and Si ions is demonstrated. Results show that the ion doses necessary for electrical isolation close-to-inversely depend on the number of ion-beam-generated atomic displacements. Results show that an increase in the dose of 2 MeV O ions (up to ∼ 2 orders of magnitude above the threshold isolation dose) and irradiation temperature (up to 350 °C) has a relatively minor effect on the thermal stability of electrical isolation, which is limited to temperatures of ∼ 300 — 400 °C. For the case of multiple-energy implantation with keV Cr, Fe, or Ni ions, the evolution of sheet resistance with annealing temperature is consistent with defect-induced isolation, with a relatively minor effect of Cr, Fe, or Ni impurities on the thermal stability of isolation. Based on these results, the mechanism for electrical isolation in ZnO by ion bombardment is discussed.


1995 ◽  
Vol 401 ◽  
Author(s):  
S. Imaduddin ◽  
R. J. Lad

AbstractThe less than 1% lattice mismatch between MgO and NiO makes them ideal candidates for investigating the growth and stability of multilayered oxide films. Ultra-thin multilayers composed of alternating films of MgO and NiO were deposited onto a stoichiometric NiO(100) single crystal substrate at 250°C by evaporating Mg and Ni in 5×10−7 Torr of O2, respectively. The structure of these multilayers was determined using LEED. Reactivity and chemical composition studies of the MgO/NiO interfaces were carried out using XPS and UPS. The MgO/NiO multilayers grow epitaxially on NiO(100), as evidenced by LEED. XPS and UPS analysis indicates attenuation of the NiO or MgO peaks during growth which is consistent with discrete layering. Chemical analysis also reveals negligible intermixing of the MgO and NiO layers during deposition. Results pertaining to the thermal stability of the multilayers show that UHV annealing above 750°C results in significant diffusion of MgO into the NiO(100) substrate.


2014 ◽  
Vol 67 (11) ◽  
pp. 1679
Author(s):  
Sheng Zhang ◽  
Qi Yang ◽  
Xiangyu Liu ◽  
Gang Xie ◽  
Qing Wei ◽  
...  

Five coordination polymers, [Cu(L)2]n (1), {[Cu(L)(Cl)(H2O)]·H2O}2n (2), [KCu(L)(μ-Cl)2]n (3), [Cu(L)(Br)H2O]n (4), and {[Cu0.5(HL)(H2O)](NO3)·H2O}2n (5) (HL = 5-methylpyrazine-2-carboxylic acid) were obtained by reactions of a pyramidal CuII-containing ligand, {[Cu(L)2(H2O)]·3H2O}n (LCu), with Gd(ClO4)3·6H2O, GdCl3·6H2O, GdCl3·6H2O/KCl, GdBr3·6H2O, or Gd(NO3)3·6H2O in water. Structural analysis reveals that the structures of these compounds range from a 0D block to a 2D network with modification of the environment of the CuII ions compared with LCu. Interestingly, there occurred a series of reversible dissolution/reorganization equilibriums between the initial reactants and the final products 1–5, which were determined as enthalpy/entropy driven chemical equilibriums by single crystal X-ray diffraction and microcalorimetry. In addition, the thermal stability of 1–4 and the magnetic property of 2 are discussed.


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