Study of Low-Energy Ion Assisted Epitaxy of Gan Films: Influence of the Initial Growth Rate

1999 ◽  
Vol 585 ◽  
Author(s):  
J. W. Gerlach ◽  
D. Schrupp ◽  
R. Schwertberger ◽  
B. Rauschenbach ◽  
A. Anders

AbstractThe deposition of thin epitaxial hexagonal gallium nitride films on c-plane sapphire by low-energy nitrogen ion assisted deposition is shown to result in films of high crystalline quality. The quality can be further heightened by using the concept of an isothermal growth rate ramp. Characterization of film structure, defect density distribution and surface topography by XRD, RBS/C, and AFM, respectively, reveals the importance of the nitrogen ion energy and the ion to atom ratio on the film properties.

2016 ◽  
Vol 18 (1) ◽  
pp. 458-465 ◽  
Author(s):  
Hisao Kiuchi ◽  
Takahiro Kondo ◽  
Masataka Sakurai ◽  
Donghui Guo ◽  
Junji Nakamura ◽  
...  

The well-controlled nitrogen doped graphite with graphitic nitrogen located in the zigzag edge and/or vacancy sites can be realized using the low energy nitrogen sputtering. The doping mechanism of nitrogen ions is also discussed.


Author(s):  
C. Ballesteros ◽  
J. A. Garci´a ◽  
M. I. Orti´z ◽  
R. Rodri´guez ◽  
M. Varela

A detailed tribological characterization of low-energy, nitrogen implanted V5 at. %Ti alloy is presented. Samples were nitrogen-implanted at an accelerating voltage of 1.2 kV and 1 mA/cm2, up to a dose of 1E19 ions/cm2. The tribological properties of the alloys: microhardness, friction coefficient and wear resistance, have improved after ion implantation and this improvement increases as the implantation temperature increases. The microstructure of the alloys were analysed by transmission electron microscopy. A direct correlation between structural modifications of the nitrogen implanted layer and the improvement in their tribological properties is obtained. For samples implanted at 848 K a nanocomposite layer where the reinforcement particles are TiN precipitates forms. TiN precipitation appears as the responsible of the improvement in the tribological properties.


2001 ◽  
Vol 664 ◽  
Author(s):  
Jennifer Heath ◽  
Suman B. Iyer ◽  
Yoram Lubianiker ◽  
J. David Cohen ◽  
Gautam Ganguly

ABSTRACTWe have carried out measurements to try to correlate amorphous silicon film properties with companion solar cell device performance. The dc plasma deposited intrinsic films were prepared with various hydrogen dilution levels, and increasing power levels to increase growth rate. The electronic properties were determined using admittance spectroscopy and drive-level capacitance profiling (DLCP) techniques as well as transient photocapacitance and photocurrent spectroscopy. Cell and film performance were explored in both as-grown and light-soaked states. We observed that, although cell performance decreased systematiclly with increasing growth rate, it depended on factors other than the deep defect density in the matched films. On the other hand, we did observe that increases in defect density caused by the light-induced degradation led to fairly predictable decreases in the cell fill factors.


Author(s):  
Takayuki Shima ◽  
Yunosuke Makita ◽  
Shinji Kimura ◽  
Tsutomu Iida ◽  
Hirokazu Sanpei ◽  
...  

2003 ◽  
Vol 81 (11) ◽  
pp. 1293-1302
Author(s):  
S Abdesselem ◽  
A Ouhab ◽  
M S Aida

We deposit thin films of a-Si:H by RF diode spray on substrate with temperatures varying from 200 to 500 °C. Knowing that this deposition method is violent when compared with the plasma-assisted deposition method, we have used low RF power to limit the energy of the Ar ions bombarding the surface of the growing film. Characterization of the films by UV–visible absorption spectroscopy suggests that the influence of the substrate temperature can be classified into three different regimes: (i) low temperature, Ts < 300 °C: the films show a strong disorder, the hydrogen is bound only in the polyhydric configuration; (ii) intermediate temperature, 300 °C < Ts < 400 °C: film growth is rapid, the films present a lower defect density; this may be the best regime to make good quality a-Si:H films using the spraying method; (iii) high temperature, Ts > 400 °C: the films are more organized, but less hydrogenated. The substrate temperature influences the film properties by modifying the growing mechanism through a control of the reactions taking place at the plasma–substrate interface, where the hydrogen dynamics play a fundamental role.[Journal translation]


2004 ◽  
Vol 815 ◽  
Author(s):  
H. Tsuchida ◽  
I. Kamata ◽  
S. Izumi ◽  
T. Tawara ◽  
T. Jikimoto ◽  
...  

AbstractGrowth technique for thick SiC epilayers with a reduced micropipe density has been developed in a vertical hot-wall CVD reactor. Micropipe closing by growing an epilayer is possible with a nearly 100% probability for 4H-SiC substrates oriented (0001) and (000-1) off-cut towards either [11-20] or [1-100]. By applying the micropipe closing technique, a high-performance Schottky barrier diode (SBD) was demonstrated on a substrate including micropipes. Growth of low-doped and thick SiC epilayers is also possible with a good morphology at a high growth rate, and 14.4 kV blocking performance was demonstrated using a 210 μm-thick epilayer. Epitaxial growth on (000-1) substrates with low doping and a low epi-induced defect density was also demonstrated. Deep centers and impurities were investigated to determine the effective lifetime killer of the epilayers. Dislocations and stacking faults in epilayers grown on 4H-SiC substrates off-cut towards different directions were also investigated.


2012 ◽  
Vol 711 ◽  
pp. 27-30 ◽  
Author(s):  
Andrea Severino ◽  
Ruggero Anzalone ◽  
Massimo Camarda ◽  
Nicolò Piluso ◽  
Francesco La Via

In this work, we focus our attention on the characterization of 3C-SiC films, grown within a CVD reactor, on Si substrates. It will be shown how the growth procedures influence the SiC film structure and quality with the growth rate used during the growth used as example. Evaluation of crystal structure has been conducted by X-Ray Diffraction (XRD), Raman microscopy and Transmission Electron Microscopy (TEM). Overall film quality increases if films are grown under low growth rate conditions, thanks also to an important reduction in the density of micro-twins. The trend of the full widths at half maximum (FWHMs) of SiC rocking curves, considered good ‘quality indicator’ as their broadenings are affected by crystallographic defects, as a function of 3C-SiC thickness shows a saturated regime for very thick films, due to the saturation of stacking fault density after 50 μm of growth. This work wants to suggest a reasonable path for the characterization of the material structure that can be useful, anywhere and in any time, to assess if the morphology and microstructure of our films are satisfactory and to drive towards the desired improvement.


1994 ◽  
Vol 116 (4) ◽  
pp. 870-876 ◽  
Author(s):  
R. Wei ◽  
B. Shogrin ◽  
P. J. Wilbur ◽  
O. Ozturk ◽  
D. L. Williamson ◽  
...  

The effects of nitrogen implantation conditions (ion energy, dose rate, and processing time) on the thickness and wear behavior of N-rich layers produced on 304 stainless-steel surfaces are examined. Surfaces implanted at elevated temperatures (≈400°C) with 0.4 to 2 keV nitrogen ions at high dose rates (1.5 to 3.8 mA/cm2) are compared to surfaces implanted at higher energies (30 to 60 keV) and lower current densities (0.1 to 0.25 mA/cm2). The most wear-resistant surfaces are observed when the implanted-ion energy is near 1 keV and the dose is very large (> 2 × 1019 ions/cm2). Typically, surfaces implanted under these optimum conditions exhibit load-bearing capabilities at least 1000 times that of the untreated material. Some comparisons are also made to surfaces processed using conventional plasma-nitriding. Samples treated using either process have wear-resistant surface layers in which the nitrogen is in solid solution in the fcc phase. It is argued that the deep N migration (> 1 μm) that occurs under low-energy implantation conditions is due to thermal diffusion that is enhanced by a mechanism other than radiation-induced vacancy production.


1995 ◽  
Vol 377 ◽  
Author(s):  
I. S. Osborne ◽  
N. Hata ◽  
A. Matsuda

ABSTRACTHydrogenated amorphous silicon containing chlorine (a-Si:H (Cl)) films have been grown by plasma enhanced chemical vapor deposition from a mixture of silane and dichlorosilane with a dichlorosilane concentration up to 60%. We report on the film properties in the as-deposited state and the behavior of the films under both high intensity pulsed laser illumination and long-term AMI illumination. With increasing dichlorosilane concentration the films show an increased resilience to the creation of light induced defects, as determined from the constant photocurrent method. After 900 hours under AMI illumination, the defect density shows a minimum (< 1016 cnr−3) for a 10 % mixing ratio.


2018 ◽  
Vol 39 (1) ◽  
pp. 1-22 ◽  
Author(s):  
Nikolay S. Peev

Abstract Characterization of the liquid phase epitaxial growth is in the scope of the present paper. The determination of the main parameters of the process such as the stationary growth rate, the time constant, the stationary supercooling, the kinetic coefficient, the initial growth rate, the crystallization mechanism are under consideration. Pursuing this aim a differential equation has been obtained which allows obtaining the dependences of the supersaturation, the growth rate and the growth layer thickness on the duration of growth. These dependences allow the determination of the above mentioned process parameters. Two mechanisms of crystallization are considered - the normal growth and the growth assisted by the screw dislocations. The two dimensional nuclei growth has not been considered because an analytical solution of the equation was not possible. Some of the theoretical contentions are confirmed by the experiments. Using the obtained values of the parameters dependences are defined. Good agreement between theory and experimental results is observed.


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