Evaluation of Deep Level Transient Spectra Originating from Continuous Distributions of Deep Energy Levels

1991 ◽  
Vol 124 (1) ◽  
pp. 295-309 ◽  
Author(s):  
K. Tittelbach-Helmrich
Keyword(s):  
Deep Level ◽  
Energy Levels ◽  
Continuous Distributions ◽  
Transient Spectra

Electrical Properties of the Multilayer Structures Based on Ultrathin Diamond-Like Carbon Films

1996 ◽  
Vol 452 ◽  
Author(s):  
V. I. Polyakov ◽  
P. I. Perov ◽  
N. M. Rossukanyi ◽  
A. I. Rukovishnikov ◽  
A. V. Khomich ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Band Gap ◽  
Cross Sections ◽  
Deep Level ◽  
Energy Levels ◽  
Differential Resistance ◽  
Carbon Films ◽  
Multilayer Structures ◽  
Transient Spectra ◽  
Trapping Centers

AbstractThe electrical characteristics of multilayer structures based on amorphous ultrathin diamondlike carbon films were investigated including dynamic and quasi-static current-voltage characteristics, capacitance-voltage characteristics, deep level transient spectra. The effect of illumination and temperature on these characteristics was also investigated. For the multilayer structures composed of lower band gap amorphous carbon layers separated with higher band gap ones, there were observed well-defined regions of negative differential resistance and sharp 20-fold changes in capacitance at definite voltages. Activation energies, capture cross sections, and locations of trapping centers were defined. The effects observed are discussed in terms of trap-assisted tunneling and, also, in terms of resonant tunneling between energy levels in superlattices and charge filling of the quantum wells and trapping centers.

The Defect Structure of BaTiO3 Thin Films

1993 ◽  
Vol 310 ◽  
Author(s):  
L.A. Wills ◽  
B.W. Wessels
Keyword(s):  
Thin Films ◽  
Cross Section ◽  
Defect Structure ◽  
Oxygen Vacancies ◽  
Vacuum Annealing ◽  
Deep Level ◽  
Energy Levels ◽  
The Other ◽  
Optical Cross Section ◽  
Impurity Defects

AbstractThe defect structure of BaTiO3 thin films grown on (100) Si was examined using transient photocapacitance spectroscopy. The concentration, optical cross section and associated energy levels of both native and impurity defects in as-grown and annealed BaTiO3 films were evaluated. Deep level defects withpeak energies of Ev+1.8, Ev+2.4, Ev+2.7, Ev+3.0-3.1 and Ev+3.2-3.3 eV were observed in the as-grown films. Upon vacuum annealing, the concentration of the traps at Ev+3.0 and Ev+3.2 eV increased while the concentration of the traps at Ev+ 1.8 and Ev+2.4 eV decreased. The levels at Ev+3.0-3.1 and Ev+3.2-3.3 eV are attributed to oxygen vacancies. The other levels are tentatively ascribed to Fe and Fe related defects.

THERMAL CURRENTS FROM UNDOPED SEMI-INSULATING GaAs MONITORED BY CHARGE DEEP-LEVEL TRANSIENT SPECTROSCOPY

1995 ◽  
Vol 09 (23) ◽  
pp. 3099-3114
Author(s):  
I. THURZO ◽  
K. GMUCOVÁ ◽  
F. DUBECKÝ ◽  
J. DARMO
Keyword(s):  
Space Charge ◽  
Space Charge Region ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Energy Levels ◽  
Thermally Stimulated Currents ◽  
Metal Semiconductor Metal ◽  
Transient Spectroscopy ◽  
Electrical Bias

Metal-semiconductor-metal (MSM) devices prepared from crystalline undoped semi-insulating GaAs were investigated by charge deep-level transient spectroscopy (QDLTS), while exciting the devices by electrical bias pulses in dark. Unlike current concepts of the QDLTS response, thermally stimulated currents were integrated from devices with GaAs crystals thinned down to or below 200 µm and equipped with Au electrodes. Au-GaAs-Au structures on 230 µm thick crystals exhibited standard QDLTS response on either cooling or heating between 100 K and 250 K. It is concluded that a macroscopic space charge region of width ≈10−7 m is formed at the Au/GaAs interface, as the dominant energy levels became ionized. Obtained results on the peaks of the thermally stimulated charge were correlated with those of potentially identical peaks observed via optical admittance transient spectroscopy (OATS).

Deep Level Defect Studies in Mocvd-Grown InxGa1−sAs1−yNy Films Lattice-Matched to GaAs

1998 ◽  
Vol 535 ◽  
Author(s):  
Daewon Kwon ◽  
R. J. Kaplar ◽  
J. J. Boeckl ◽  
S. A. Ringel ◽  
A. A. Allerman ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Deep Level ◽  
Energy Levels ◽  
Resolution Limit ◽  
Defect States ◽  
Cross Sectional ◽  
Order Of Magnitude ◽  
Transient Spectroscopy ◽  
Lattice Matched ◽  
Dlts Spectra

AbstractDeep level defects in MOCVD-grown, unintentionally doped p-type InGaAsN films lattice matched to GaAs were investigated using deep level transient spectroscopy (DLTS) measurements. As-grown p-InGaAsN showed broad DLTS spectra suggesting that there exists a broad distribution of defect states within the band-gap. Moreover, the trap densities exceeded 1015 cm−3. Cross sectional transmission electron microscopy (TEM) measurements showed no evidence for threading dislocations within the TEM resolution limit of 107 cm−2. A set of samples was annealed after growth for 1800 seconds at 650 °C to investigate the thermal stability of the traps. The DLTS spectra of the annealed samples simplified considerably, revealing three distinct hole trap levels with energy levels of 0.10 eV, 0.23 eV, and 0.48 eV above the valence band edge with trap concentrations of 3.5 × 1014 cm−3, 3.8 × 1014 cm−3, and 8.2 × 1014 cm−3, respectively. Comparison of as-grown and annealed DLTS spectra showed that post-growth annealing effectively reduced the total trap concentration by an order of magnitude across the bandgap. However, the concentration of a trap with an energy level of 0.48 eV was not affected by annealing indicating a higher thermal stability for this trap as compared with the overall distribution of shallow and deep traps.

Hydrogen-Vacancy Complexes and their Deep States in n-Type Silicon

2015 ◽  
Vol 242 ◽  
pp. 163-168 ◽  
Author(s):  
Ilia L. Kolevatov ◽  
Frank Herklotz ◽  
Viktor Bobal ◽  
Bengt Gunnar Svensson ◽  
Edouard V. Monakhov
Keyword(s):  
Schottky Diode ◽  
Deep Level Transient Spectroscopy ◽  
Minority Carrier ◽  
Deep Level ◽  
Energy Levels ◽  
Depletion Region ◽  
Type Silicon ◽  
Oxygen Center ◽  
Hydrogen Vacancy ◽  
Transient Spectroscopy

The evolution of irradiation-induced and hydrogen-related defects in n-type silicon in the temperature range 0 – 300 °C has been studied by deep level transient spectroscopy (DLTS) and minority carrier transient spectroscopy (MCTS). Implantation of a box-like profile of hydrogen was performed into the depletion region of a Schottky diode to undertake the DLTS and MCTS measurements. Proportionality between the formation of two hydrogen-related deep states and a decrease of the vacancy-oxygen center concentration was found together with the appearance of new hydrogen-related energy levels.

Deep Levels in Superlattices

1989 ◽  
Vol 163 ◽  
Author(s):  
John D. Dow ◽  
Shang Yuan Ren ◽  
Jun Shen ◽  
Min-Hsiung Tsai
Keyword(s):  
Band Gap ◽  
Quantum Confinement ◽  
Deep Level ◽  
Energy Levels ◽  
Deep Trap ◽  
Shallow Donor ◽  
Deep Levels ◽  
Band Gap Engineering ◽  
Substitutional Impurities ◽  
Superlattice Period

AbstractThe physics of deep levels in semiconductors is reviewed, with emphasis on the fact that all substitutional impurities produce deep levels - some of which may not lie within the fundamental band gap. The character of a dopant changes when one of the deep levels moves into or out of the fundamental gap in response to a perturbation such as pressure or change of host composition. For example, Si on a Ga site in GaAs is a shallow donor, but becomes a deep trap for x>0.3 in AℓxGa1-xAs. Such shallow-deep transitions can be induced in superlattices by changing the period-widths and quantum confinement. A good rule of thumb for deep levels in superlattices is that the energy levels with respect to vacuum are relatively insensitive (on a >0.1 eV scale) to superlattice period-widths, but that the band edges of the superlattices are sensitive to changes of period. Hence the deep level positions relative to the band edges are sensitive to the period-widths, and shallow-deep transitions can be induced by band-gap engineering the superlattice periods.

Electrical Characterization of Sputter Deposition Induced Defects in n-GaN

1998 ◽  
Vol 537 ◽  
Author(s):  
F. D. Auret ◽  
S. A. Goodman ◽  
F. K. Koschnick ◽  
J.-M. Spaeth ◽  
B. Beaumont ◽  
...  
Keyword(s):  
Barrier Height ◽  
Deep Level ◽  
Energy Levels ◽  
Reverse Current ◽  
Electrical Characterization ◽  
Sputter Deposition ◽  
Nitrogen Vacancy ◽  
Transient Spectroscopy ◽  
Sputter Deposited ◽  
Induced Defects

AbstractWe have used current-voltage (I-V) measurements to assess and compare the electrical characteristics of resistively evaporated and sputter deposited Au Schottky contacts on epitaxially grown GaN. These I-V measurements revealed that resistively deposited Au contacts exhibited excellent rectification properties: high barrier height, low reverse current and good ideality factor (n = 1.04). In contrast, sputter deposited contacts had poor characteristics: low barrier height, high reverse current and non-linear forward I-V characteristics. The cause of this is thought to be defects introduced at and near the surface during sputter deposition. Deep level transient spectroscopy (DLTS) showed that at least four defects, with energy levels at 0.22±0.02 eV, 0.30±0.01 eV, 0.40±0.01 eV and 0.45±0.10 eV below the conduction band, were introduced in the GaN during sputter deposition. The first of these defects has similar electronic properties as a radiation induced defect in GaN, speculated to be the nitrogen vacancy, while the second appears to be the same as a defect in the as-grown material. The latter two defects have not previously been observed in as-grown or processed epitaxial GaN.

Effect of Phosphorus Doping and Deposition Temperature on the Deep-Level Transient Spectra in a-Si:H

1992 ◽  
Vol 31 (Part 2, No. 10B) ◽  
pp. L1460-L1462 ◽  
Author(s):  
Jun-ichi Nakata ◽  
Kazuhito Tsuchida ◽  
Shozo Imao ◽  
Yoshio Inuishi
Keyword(s):  
Deposition Temperature ◽  
Deep Level ◽  
Phosphorus Doping ◽  
Transient Spectra

Deep Level Energy Analysis of Surface and Bulk Defects Using a Noncontact Laser/Microwave Photoconductance Technique

1992 ◽  
Vol 261 ◽  
Author(s):  
A. Buczkowski ◽  
G. A. Rozgonyi ◽  
F. Shimura
Keyword(s):  
Energy Analysis ◽  
Deep Level ◽  
Energy Levels ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Level Energy ◽  
Recombination Lifetime ◽  
Recombination Processes ◽  
Bulk Energy ◽  
Recombination Velocity

ABSTRACTA noncontact technique for deep level energy analysis has been discussed based on a laser excitation/microwave reflection transient photoconductance procedure. An algorithm for separation of surface and bulk recombination effects was developed to independently determinesurface and bulk energy states. Deep energy levels associated with trapping and recombination processes have been calculated from the temperature dependence of surface recombination velocity and bulk recombination lifetime, based on state occupation statistics. Results have been compared with conventional DLTS data for silicon samples intentionally doped with metals during crystal growth.

Electrical Characterization Of Nitrogen Acceptors In p-ZnSe/p-GaAs Grown By Molecular Beam Epitaxy

1996 ◽  
Vol 442 ◽  
Author(s):  
D. Seghier ◽  
H.P. Gislason
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Deep Level ◽  
Energy Levels ◽  
Reverse Current ◽  
Electrical Characterization ◽  
Growth Conditions ◽  
Current Voltage ◽  
Major Interest ◽  
Transient Spectroscopy

AbstractUsing current-voltage measurements, deep-level transient spectroscopy and admittance spectroscopy we investigated nitrogen doped ZnSe grown on p-GaAs substrates by molecular beam epitaxy. Three major hole traps were observed with energy levels at 0. 11, 0.46, and 0.56 eV from the valence band. We attribute the level at 0.11 eV to a nitrogen acceptor. No other direct observations of this important acceptor level in p-ZnSe have been reported in the literature so far. The two remaining levels may originate from the nitrogen doping process. In addition, reverse current-voltage characteristics of the ZnSe/GaAs heterojunction show a hysteresis at low temperature and a soft saturation. At a constant reverse bias the current increases slowly until it reaches a steady state value. This behavior is attributed to a slow voltage-induced barrier lowering due to the presence of mismatch interface states. Therefore, these analyses are of a major interest for applications of ZnSe/GaAs based devices and illustrates the necessity of improving the growth conditions of such structures.

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