Thin films of rf-magnetron sputtered InN on mica: Crystallography, electrical transport, and morphology

1991 ◽  
Vol 6 (6) ◽  
pp. 1300-1307 ◽  
Author(s):  
T.J. Kistenmacher ◽  
W.A. Bryden ◽  
J.S. Morgan ◽  
D. Dayan ◽  
R. Fainchtein ◽  
...  

Reactive rf-magnetron sputtering has been employed for the growth of thin films of InN on the (001) face of mica at a variety of substrate temperatures from 50 to 550 °C. These films have been characterized by x-ray scattering, stylus profilometry, and electrical transport measurements, and their topography has been studied by SEM and STM. At low deposition temperatures, the InN films exhibit texture [(00.1)InN‖ (001)mica], while at higher deposition temperatures a large fraction of the grains are heteroepitaxial [(00.1)InN‖(001)mica, (2.0)InN · (060)mica]. The utility of the x-ray precession method in the determination of this heteroepitaxial relationship is highlighted. The films exhibit a local mobility maximum near a substrate temperature of 350 °C, beyond which a sharp increase in resistivity associated with voids and cracks owing to the onset of secondary grain growth leads to a dramatic decrease in electrical mobility. At the highest growth temperatures, however, the interconnection between grains improves and lower resistivity and higher mobility are re-established.

1992 ◽  
Vol 263 ◽  
Author(s):  
T. J. Kistenmacher ◽  
S. A. Ecelberger ◽  
W. A. Bryden

ABSTRACTThin films of (AI/In)N alloys have been deposited on AIN-nucleated (00.1) sapphire by reactive (pure N2 gas) magnetron sputtering and characterized by X-ray scattering, stylus profilometry, optical spectroscopy, and electrical transport measurements. Initial efforts have concentrated on producing films with compositions near Al0.31In0.69N (bandgap tailored to GaN). The alloy sputtering targets were disks fabricated by cold pressing appropriate molar mixtures of beads of 99.99% purity Al and In. The resulting thin films are composed of heteroepitaxial grains {(00.1)InNll(00.1)sapphire; (10.0)InNll(11.0)Sapphire} and their chemical composition has been deduced from the variation in the a cell constant (as measured by the X-ray precession method) to yield equilibrium film compositions near Al0.04In0.96N and Al0.25In0.75N, respectively. Preliminary results are presented on the dependence of the quality of heteroepitaxial growth and electrical and optical properties of. these AlxIn1−xN alloy films on various growth parameters: such as chemical composition; film thickness; morphology; and substrate temperature.


1991 ◽  
Vol 239 ◽  
Author(s):  
Ramnath Venkatraman ◽  
Paul R. Besser ◽  
Sean Brennan ◽  
John C. Bravman

ABSTRACTWe have measured elastic strain distributions with depth as a function of temperature in Al thin films of various thicknesses on oxidized silicon using synchrotron grazing incidence X-ray scattering (GIXS). Disregarding minor surface relaxation effects that depend on the film thickness, it is shown that there are no gross strain gradients in these films in the range of temperatures (between room temperature and 400°C) considered. We also observe X-ray line broadening effects, suggesting an accumulation of dislocations on cooling the films, and their annealing out as the films are reheated.


1992 ◽  
Vol 263 ◽  
Author(s):  
W. A. Bryden ◽  
S. A. Ecelberger ◽  
T. J. Kistenmacher

ABSTRACTThe correlation of low temperature electrical transport with the evolution of heteroepitaxy and morphology for sputtered indium nitride thin films has been studied. A series of indium nitride films were deposited at temperatures ranging from 50 -650 °C by reactive rf magnetron sputtering onto the (00.1) face of sapphire. Above 350 °C, a transition occurs from a continuous morphology, in which grains are in intimate electrical contact, to an open, porous morphology with poor electrical contact. This transition in morphology deeply affects the electrical transport of the semiconductor. At low deposition temperature, the electrical transport is dominated by the relatively weak intergrain scattering leading to films with moderate mobility. As the deposition temperature is raised, the increasingly porous nature of the film leads to a deterioration in electrical mobility. It is proposed here that the relevant physics of these films is analogous to that for granular solids with a distribution of electrical connectivities that suggests a scattering potential dominated by disorder. In fact, the temperature dependence of the resistivity is found to be analogous to that observed in disordered and amorphous materials. In particular, the resistivity is characterized by: 1) A very weak temperature dependence; 2) The observation of a resistance minimum; and, 3) A steep rise in the low temperature (<4K) resistivity that follows a T1/ dependence.


2010 ◽  
Vol 25 (S1) ◽  
pp. S36-S39 ◽  
Author(s):  
Tieying Yang ◽  
Xiubo Qin ◽  
Huan-hua Wang ◽  
Quanjie Jia ◽  
Runsheng Yu ◽  
...  

Transparent p-type conducting Ga-doped SnO2 thin films were prepared using reactive rf-magnetron sputtering. Good p-type conduction was directly realized without the need of postdeposition annealing. The p-type conductivity was found to be very sensitive to the growth condition and process, suggesting that the carrier behavior is strongly related to the fine microstructure of the films. The microstructures of the films were characterized using synchrotron X-ray diffraction and specular reflectivity techniques. The valence state of the Ga dopant was measured from X-ray photoelectron spectra to explain the origin of net holes presented in the films.


2016 ◽  
Vol 49 (4) ◽  
pp. 1308-1314 ◽  
Author(s):  
Christophe Lefevre ◽  
Alexandre Thomasson ◽  
Francois Roulland ◽  
Vincent Favre-Nicolin ◽  
Yves Joly ◽  
...  

The cationic distribution is decisive for both the magnetic and electric properties of complex oxides. While it can be easily determined in bulk materials using classical methods such as X-ray or neutron diffraction, difficulties arise for thin films owing to the relatively small amount of material to probe. It is shown here that a full determination of the cationic site distribution in thin films is possible through an optimized processing of resonant elastic X-ray scattering experiments. The method is illustrated using gallium ferrite Ga2−xFexO3samples which have been the focus of an increasing number of studies this past decade. They indeed represent an alternative to the, to date, only room-temperature magnetoelectric compound BiFeO3. The methodology can be applied to determine the element distribution over the various crystallographic sites in any crystallized system.


2010 ◽  
Vol 654-656 ◽  
pp. 1748-1751
Author(s):  
Yang Ping Li ◽  
Zheng Tang Liu ◽  
Feng Yan ◽  
Wen Ting Liu

Germanium carbon films were prepared on ZnS substrates by reactive RF magnetron sput- tering of a Ge target in Ar and CH4 mixtures for IR antireflective and protective purposes. IR transmit- ttance spectra of the specimens were measured, with which H content in the films was investigated. The C and Ge contents and the atomic binding state were studied by X-ray photoelectron spectroscopy. The results show that H involved in the films combine mainly with C at low substrate temperatures. IR absorption peaks caused by the C-H bonds decrease with increasing temperature, indicating the drop of the C-H bonds content in the film. At relatively low temperature the film is high in C content and low in refractive index; at high temperature the film is low in C content and high in refractive index. Both C-Ge and C-C bonds exist in the film and O impurity combines mainly with Ge.


1993 ◽  
Vol 312 ◽  
Author(s):  
Wayne A. Bryden ◽  
Marilyn E. Hawley ◽  
Scott A. Ecelberger ◽  
Thomas J. Kistenmacher

AbsiractThe evolution of the growth morphology of thin films of InN on (00.1) sapphire and on (00.1) sapphire prenudeated by a layer of AIN have been followed as a function of the thickness of the InN overlayer. The InN thin films and the AIN nucleation layers were deposited by reactive magnetron sputtering and first characterized by X-ray scattering, profilometry, and electrical transport. These AIN-nucleated InN films displayed heteroepitaxial grains, and high Hall mobility -even in the limit of InN overlayer on the order of 20-40Å. In parallel, InN films of varying thickness were grown directly onto (00.1) sapphire. These films showed a mixture of textured and heteroepitaxial grains, and lower Hall mobility. Atomic force and scanning tunneling microscopy studies have focussed on the morphology of the InN films with thicknesses: (a) much smaller than the AIN nucleation layer; and, (b) near the morphological transition that occurs at ∼1μm and has been attributed to the crossover from a 2D to a 3D growth mechanism. Additional correlations of X-ray structural coherence with growth mode are also examined.


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