Chemistry, microstructure, and electrical properties at interfaces between thin films of titanium and alpha (6H) silicon carbide (0001)

1995 ◽  
Vol 10 (3) ◽  
pp. 668-679 ◽  
Author(s):  
L.M. Porter ◽  
R.F. Davis ◽  
J.S. Bow ◽  
M.J. Kim ◽  
R.W. Carpenter ◽  
...  

Epitaxial thin films (4–1000 Å) of Ti contacts have been deposited via UHV electron beam evaporation at room temperature on monocrystalline, n-type, alpha (6H)-SiC(0001). The interfacial chemistry and microstructure, and the electrical properties, were investigated at room temperature and after annealing at 700 °C up to 60 min. High resolution TEM analyses revealed the formation during annealing of reaction zones consisting of Ti5Si3 and TiC. The corresponding electrical properties exhibited considerable stability except after an initial 20 min anneal. Current-voltage (I-V) measurements showed that the Ti contacts were rectifying with low ideality factors (n < 1.09) and typical leakage currents of 5 × 10−7 A/cm2 at −10 V. The Schottky barrier heights calculated from x-ray photoelectron spectroscopy and I-V and V-V measurements were between 0.79 and 0.88 eV for the as-deposited contacts and between 0.86 and 1.04 eV for the annealed contacts.

1995 ◽  
Vol 10 (1) ◽  
pp. 26-33 ◽  
Author(s):  
L.M. Porter ◽  
R.F. Davis ◽  
J.S. Bow ◽  
M.J. Kim ◽  
R.W. Carpenter

Thin films (4–1000 Å) of Co were deposited onto n-type 6H-SiC(0001) wafers by UHV electron beam evaporation. The chemistry, microstructure, and electrical properties were determined using x-ray photoelectron spectroscopy, high resolution transmission electron microscopy, and I-V and C-V measurements, respectively. The as-deposited contacts exhibited excellent rectifying behavior with low ideality factors and leakage currents of n < 1.06 and 2.0 × 10−8 A/cm2 at −10 V, respectively. During annealing at 1000 °C for 2 min, significant reaction occurred resulting in the formation of CoSi and graphite. These annealed contacts exhibited ohmic-like character, which is believed to be due to defects created in the interface region.


1995 ◽  
Vol 10 (9) ◽  
pp. 2336-2342 ◽  
Author(s):  
L.M. Porter ◽  
R.F. Davis ◽  
J.S. Bow ◽  
M.J. Kim ◽  
R.W. Carpenter

Thin films (4-1000 Å) of Pt were deposited via UHV electron beam evaporation at room temperature on monocrystalline, n-type α (6H)-SiC(0001) substrates and examined in terms of chemistry, microstructure, and electrical properties. The as-deposited contacts were polycrystalline and showed excellent rectifying behavior with low ideality factors (n < 1.1) and leakage currents of 5 × 10−8 A/cm2 at −10 V. The Schottky barrier height increased from 1.06 eV before annealing to 1.26 eV after successive 20 min anneals at 450, 550, 650, and 750 °C. In addition, the leakage currents decreased to 2 × 10−8 A/cm2 at −10 V. Interfacial reactions were not observed at annealing temperatures below 750 °C; above this temperature, Pt2Si and C precipitates were identified in the reaction zone.


1992 ◽  
Vol 282 ◽  
Author(s):  
L. M. Porter ◽  
R. C. Glass ◽  
R. F. Davis ◽  
J. S. Bow ◽  
M. J. Kim ◽  
...  

ABSTRACTThin films (2 Å - 1000 Å) of titanium, platinum, and hafnium were deposited via UHV electron beam evaporation at room temperature on n-type, (0001) alpha (6H)-SiC and compared in terms of interfacial chemistry, energy barriers to electrical conduction, and macroscopic electrical behavior. Current-voltage measurements have shown that these contacts are rectifying, all with ideality factors between 1.01 and 1.09. The lowest leakage currents (∼5 × 10−8 A/cm2 at -10 V) were determined for unannealed Pt contacts and for Hf contacts annealed at 700°C for 20 minutes. Current-voltage (I-V), capacitance-voltage (C-V), and x-ray photoelectron spectro-scopy (XPS) were among the techniques used to determine barrier heights, all of which were within a few tenths of an electron volt of 1.0 eV. The narrow range of calculated barrier heights along with the XPS valence spectrum of the chemically prepared SiC surface give evidence that the Fermi level is pinned at the semiconductor surface.


2013 ◽  
Vol 1507 ◽  
Author(s):  
Ryosuke Yamauchi ◽  
Geng Tan ◽  
Daishi Shiojiri ◽  
Nobuo Tsuchimine ◽  
Koji Koyama ◽  
...  

ABSTRACTWe examined the influence of momentary annealing on the nanoscale surface morphology of NiO(111) epitaxial thin films deposited on atomically stepped sapphire (0001) substrates at room temperature in O2 at 1.3 × 10−3 and 1.3 × 10−6 Pa using a pulsed laser deposition (PLD) technique. The NiO films have atomically flat surfaces (RMS roughness: approximately 0.1–0.2 nm) reflecting the step-and-terrace structures of the substrates, regardless of the O2 deposition pressure. After rapid thermal annealing (RTA) of the NiO(111) epitaxial film deposited at 1.3 × 10−3 Pa O2, a periodic straight nanogroove array related to the atomic steps of the substrate was formed on the film surface for 60 s. In contrast, the fabrication of a transient state in the nanogroove array formation was achieved with RTA of less than 1 s. However, when the O2 atmosphere during PLD was 1.3 × 10−6 Pa, random crystal growth was observed and resulted in a disordered rough surface nanostructure after RTA.


2002 ◽  
Vol 750 ◽  
Author(s):  
Yoshifumi Aoi ◽  
Kojiro Ono ◽  
Kunio Sakurada ◽  
Eiji Kamijo

ABSTRACTAmorphous CNx thin films were deposited by pulsed laser deposition (PLD) combined with a nitrogen rf radical beam source which supplies active nitrogen species to the growing film surface. The deposited films were characterized by X-ray photoelectron spectroscopy (XPS), Raman scattering, and Fourier transform infrared (FTIR) spectroscopy. Nitrogen content of the deposited films increased with increasing rf input power and N2 pressure in the PLD chamber. The maximum N/C ratio 0.23 was obtained at 400 W of rf input power and 1.3 Pa. XPS N 1s spectra shows the existence of several bonding structures in the deposited films. Electrical properties of the deposited films were investigated. The electrical conductivity decreased with increasing N/C atomic ratio. Temperature dependence of electrical conductivity measurements indicated that electronic conduction occurred by variable-range hopping between p electron localized states.


2012 ◽  
Vol 38 ◽  
pp. S73-S77 ◽  
Author(s):  
Xiaohua Zhang ◽  
Wei Ren ◽  
Peng Shi ◽  
M. Saeed Khan ◽  
Xiaofeng Chen ◽  
...  

2017 ◽  
Vol 25 (2) ◽  
pp. 243-250
Author(s):  
Nguyen Nang Dinh ◽  
Le Dinh Trong ◽  
Pham Duy Long

Bulk nanostructured perovskites of La0.67-xLi3xTiO3 (LLTO) were prepared by using thermally ball-grinding from compounds of La2O3, Li2CO3 and TiO2. From XRD analysis, it was found that LTTO materials were crystallized with nano-size grains of an average size of 30 nm. The bulk ionic conductivity was found strongly dependent on the Li+ composition, the samples with x = 0.11 (corresponding to a La0.56Li0.33TiO3 compound) have the best ionic conductivity, which is ca. 3.2 x 10-3 S/cm at room temperature. The LLTO amorphous films were made by electron beam deposition. At room temperature the smooth films have ionic conductivity of 3.5 x 10-5  S/cm and transmittance of 80%. The optical bandgap of the films was found to be of 2.3 eV. The results have shown that the perovskite La0.56Li0.33TiO3  thin films can be used for a transparent solid electrolyte in ionic battery and in all-solid-state electrochromic devices, in particular.    


2019 ◽  
Vol 14 (29) ◽  
pp. 37-43 ◽  
Author(s):  
Raied K. Jamal

The electrical properties of pure NiO and NiO:Au Films which aredeposited on glass substrate with various dopant concentrations(1wt.%, 2wt%, 3wt.% and 4wt.%) at room temperature 450 Coannealing temperature will be presented. The results of the hall effectshowed that all the films were p-type. The Hall mobility decreaseswhile both carrier concentration and conductivity increases with theincreasing of annealing temperatures and doping percentage, Thus,indicating the behavior of semiconductor, and also the D.Cconductivity from which the activation energy decrease with thedoping concentration increase and transport mechanism of the chargecarriers can be estimated.


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