Impurity Conduction in n-Type 4H-SIC

1996 ◽  
Vol 423 ◽  
Author(s):  
A. O. Evwaraye ◽  
S. R. Smith ◽  
W. C. Mitchel ◽  
M. D. Roth
Keyword(s):  
Activation Energies ◽  
Hopping Conduction ◽  
Admittance Spectroscopy ◽  
Temperature Dependent ◽  
Resistivity Measurements ◽  
Nitrogen Levels ◽  
Impurity Conduction ◽  
Measured Activation ◽  
Temperature Dependent Resistivity ◽  
Type Sample

AbstractImpurity conduction (or hopping conduction) has been observed in the more heavily n-type 4H-SiC samples by both temperature dependent resistivity measurements and thermal admittance spectroscopy. The measured activation energies ɛ 3 for hopping were 4–5 meV and 2.3–3.0 meV respectively. No evidence of hopping conduction was seen by either method in the sample where ND-NA < 1018 cm-3. The thermal admittance spectrum of the lightly n-type sample showed the two nitrogen levels at 53 and 100 meV.

The comparative studies of chemical vapor deposition grown epitaxial layers and of sublimation sandwich method grown 4H-SiC samples

1999 ◽  
Vol 572 ◽  
Author(s):  
A. O. Evwaraye ◽  
S. R. Smith ◽  
W. C. Mitchel
Keyword(s):  
Activation Energy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Energy Levels ◽  
Chemical Vapor ◽  
Hopping Conduction ◽  
Admittance Spectroscopy ◽  
Nitrogen Levels ◽  
Capacitance Voltage ◽  
Sandwich Method

ABSTRACTThermal admittance spectroscopy was used to characterize the shallow dopants in chemical vapor deposition ( CVD) grown thin films and in sublimation sandwich method ( SSM) grown 4H-SiC layers. The values of the activation energy levels of EC − 0.054 eV for Nitrogen at the hexagonal site and of EC − 0.10 eV for Nitrogen at the cubic site were indices of comparison. The net carrier concentrations ( ND − NV ) of the films were determined by capacitance-voltage measurements. The net carrier concentrations for the SSM films ranged from 2 × 1017 to 7 × 1017 cm−3. The two Nitrogen levels were observed in the CVD films. Hopping conduction with an activation energy of EC −0.0058 eV was observed in one SSM sample having ND − NV = 7 × 1017 cm−3.

Impurity Conduction in Silicon Carbide

2007 ◽  
Vol 556-557 ◽  
pp. 367-370 ◽  
Author(s):  
Michael Krieger ◽  
Kurt Semmelroth ◽  
Heiko B. Weber ◽  
Gerhard Pensl ◽  
Martin Rambach ◽  
...  
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Low Temperatures ◽  
Nearest Neighbor ◽  
Arrhenius Plot ◽  
Schottky Contacts ◽  
Steep Slope ◽  
Admittance Spectroscopy ◽  
Resistivity Measurements ◽  
Impurity Conduction

We report on admittance spectroscopy (AS) investigations taken on aluminum (Al)- doped 6H-SiC crystals at low temperatures. Admittance spectra taken on Schottky contacts of highly doped samples (NA ≥ 7.2×1017 cm-3) reveal two series of conductance peaks, which cause two different slopes of the Arrhenius plot. The steep slope is attributed to the Al acceptor, while the flatter one - obtained from the low temperature peaks - is attributed to the activation energy ε3 of nearest neighbor hopping. We propose a model, which explains the unexpected sharpness of the low temperature conductance peaks and the disappearance of these peaks for low acceptor concentrations. The model is verified by simulation, and the AS results are compared with corresponding results obtained from resistivity measurements taken on 4H- and the identical 6HSiC samples.

Deep Level near EC – 0.55 eV in Undoped 4H-SiC Substrates

2006 ◽  
Vol 527-529 ◽  
pp. 505-508
Author(s):  
W.C. Mitchel ◽  
William D. Mitchell ◽  
S.R. Smith ◽  
G.R. Landis ◽  
A.O. Evwaraye ◽  
...  
Keyword(s):  
Hall Effect ◽  
Deep Level ◽  
Activation Energies ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Admittance Spectroscopy ◽  
Temperature Dependent ◽  
Thermally Stimulated Current ◽  
Commercial Grade ◽  
Transport Technique

A variety of 4H-SiC samples from undoped crystals grown by the physical vapor transport technique have been studied by temperature dependent Hall effect, optical and thermal admittance spectroscopy and thermally stimulated current. In most samples studied the activation energies were in the range 0.9 - 1.6 eV expected for commercial grade HPSI 4H-SiC. However, in several samples from developmental crystals a previously unreported deep level at EC-0.55 ± 0.01 eV was observed. Thermal admittance spectroscopy detected one level with an energy of about 0.53 eV while optical admittance spectroscopy measurements resolved two levels at 0.56 and 0.64 eV. Thermally stimulated current measurements made to study compensated levels in the material detected several peaks at energies in the range 0.2 to 0.6 eV.

Activation energies in diamond films evaluated using admittance spectroscopy and resistivity measurements

2007 ◽  
Vol 101 (3) ◽  
pp. 033714 ◽  
Author(s):  
Adenilson J. Chiquito ◽  
Olívia M. Berengue ◽  
Edgar Diagonel ◽  
José C. Galzerani ◽  
João R. Moro
Keyword(s):  
Diamond Films ◽  
Activation Energies ◽  
Admittance Spectroscopy ◽  
Resistivity Measurements

Thermal And Optical Admittance Spectroscopy Studies Of Defects In 15r-Sic

1996 ◽  
Vol 423 ◽  
Author(s):  
S. R. Smith ◽  
A. O. Evwaraye ◽  
W. C. Mitchel
Keyword(s):  
Admittance Spectroscopy ◽  
Temperature Dependent ◽  
Nitrogen Levels ◽  
Spin Resonance ◽  
Hall Effect Measurements ◽  
Heavily Doped ◽  
The Common ◽  
Spectroscopy Studies ◽  
Cv Measurements ◽  
Spectroscopy Optical

AbstractNitrogen is the common n-type dopant of the various polytypes of silicon carbide. The nitrogen levels in 4H-SiC (at EC-53 meV and EC-100 meV) and in 6H-SiC (at EC-89 meV, EC- 100 meV, and EC-125 meV) have been studied in detail by temperature dependent Hall effect measurements, electron spin resonance (ESR), and thermal admittance spectroscopy. Until now, such detailed studies of the nitrogen levels in 15R-SiC have not been carried out.Lely-grown 15R samples were used in these studies. The net carrier concentrations (ND-NA), determined by room temperature CV measurements, ranged from 1 × 1018 to 3 × 1018 cm−3. The nitrogen levels in 15R-SiC were studied using thermal admittance spectroscopy. Optical admittance spectroscopy (OAdS) was used to study the deeper defects in this polytype. It was found that optical transitions to the conduction band were inhibited in the heavily doped material.

INTERESTING RESISTIVITY BEHAVIOR OF THE Ag–Ni–Si SILICIDE FILMS FORMED AT 850°C BY RAPID THERMAL ANNEALING OF THE Ag–Ni/Si FILMS

2011 ◽  
Vol 25 (28) ◽  
pp. 3773-3783 ◽  
Author(s):  
G. UTLU
Keyword(s):  
Grain Boundary ◽  
Film Thickness ◽  
Temperature Dependent ◽  
Dominant Mechanism ◽  
Resistivity Measurements ◽  
Temperature Range ◽  
Dependent Behavior ◽  
Temperature Dependent Resistivity ◽  
Si Films ◽  
Total Resistivity

The temperature-dependent resistivity measurements of our Ag – Ni – Si silicide films with 51–343 nm thicknesses are studied as a function of temperature and film thickness over the temperature range of 100–900 K. The most striking behavior is that the variation of the resistivity of the Ag – Ni – Si silicide films with temperature exhibits an unusual temperature-dependent behavior with respect to those of the transition and untransition metals. Our measurements show that the total resistivity of the Ag – Ni – Si silicide films increases linearly with temperature up to a Tm temperature at which resistivity reaches a maximum thereafter Tm decreases rapidly and finally to zero at ~850 K. Tm temperature is found to decrease with decreasing film thickness. We have shown that in the temperature range of 100-Tm K, electron–phonon resistivity and grain boundary resistivity components responsible for the total resistivity increase. But the grain boundary scattering is dominant mechanism for the resistivity increase in our Ag – Ni – Si silicide films.

Enhanced Néel temperature in EuSnP under pressure

2019 ◽  
Vol 48 (16) ◽  
pp. 5327-5334 ◽  
Author(s):  
Xin Gui ◽  
Gregory J. Finkelstein ◽  
David E. Graf ◽  
Kaya Wei ◽  
Dongzhou Zhang ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Transition Temperature ◽  
Structural Phase ◽  
Antiferromagnetic Transition ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Resistivity Measurements ◽  
Temperature Dependent Resistivity

The high-pressure single crystal X-ray diffraction results for EuSnP are reported with no structural phase transition below ∼6.2 GPa. Temperature-dependent resistivity measurements up to 2.15 GPa indicate that the antiferromagnetic transition temperature (TN) is significantly enhanced under pressure.

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