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.

scholarly journals Electrical Characterization of Sputter Deposition Induced Defects in n-GaN

1999 ◽  
Vol 4 (S1) ◽  
pp. 612-617 ◽  
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

We 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.

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.

scholarly journals Electrical Characterization of Metastable Defects Introduced in GaN by Eu-Ion Implantation

2011 ◽  
Vol 679-680 ◽  
pp. 804-807 ◽  
Author(s):  
F. Danie Auret ◽  
Walter E. Meyer ◽  
M. Diale ◽  
P.J. Janse Van Rensburg ◽  
S.F. Song ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Deep Level ◽  
Energy Levels ◽  
Electrical Characterization ◽  
Defect States ◽  
First Order Kinetics ◽  
Transient Spectroscopy ◽  
Induced Defects ◽  
Transformation Processes

Gallium nitride (GaN), grown by HVPE, was implanted with 300 keV Eu ions and then annealed at 1000 oC . Deep level transient spectroscopy (DLTS) and Laplace DLTS (L-DLTS) were used to characterise the ion implantation induced defects in GaN. Two of the implantation induced defects, E1 and E2, with DLTS peaks in the 100 – 200 K temperature range, had DLTS signals that could be studied with L-DLTS. We show that these two defects, with energy levels of 0.18 eV and 0.27 eV below the conduction band, respectively, are two configurations of a metastable defect. These two defect states can be reproducibly removed and re-introduced by changing the pulse, bias and temperature conditions, and the transformation processes follow first order kinetics.

Electrical Characterization of N+-implanted n-type ZnO Single Crystals: p-n Homojunction and Deep Level Defects

2007 ◽  
Vol 1035 ◽  
Author(s):  
Qilin Gu ◽  
Xuemin Dai ◽  
Chi-Chung Ling ◽  
Shijie Xu ◽  
Liwu Lu ◽  
...  
Keyword(s):  
Single Crystals ◽  
Thermal Evolution ◽  
Deep Level ◽  
Schottky Diodes ◽  
Control Sample ◽  
Electrical Characterization ◽  
Type Layer ◽  
Current Voltage ◽  
Transient Spectroscopy ◽  
Induced Defects

AbstractUnintentionally doped n-type ZnO single crystals were implanted by nitrogen ions with different fluences of 1013, 1014 and 1015 cm−2 respectively. ZnO p-n homojunction was successfully fabricated due to the formation of p-type layer after 650°C post-implantation annealing in air for 30 minutes. Further thermal evolution of deep level defects was studied through thermal annealing up to 1200°C. Electrical characterization techniques including current-voltage (I-V), capacitance-voltage (C-V), Deep Level Transient Spectroscopy (DLTS) and double-correlation DLTS (DDLTS) were used for investigating the control sample, all the as-implanted and annealed samples through Au/n-ZnO Schottky diodes as well as ZnO p-n junctions. Detailed electrical properties of fabricated devices and characteristics of implantation induced defects were analyzed based on plentiful DLTS spectra. Moreover, low-temperature photoluminescence experiments of all the as-implanted and annealed samples were performed and the correlation between results from electrical and optical characterizations was discussed.

Metal In-Diffusion during Fe and Co-Germanidation of Germanium

2007 ◽  
Vol 131-133 ◽  
pp. 47-52 ◽  
Author(s):  
Eddy Simoen ◽  
K. Opsomer ◽  
Cor Claeys ◽  
Karen Maex ◽  
Christophe Detavernier ◽  
...  
Keyword(s):  
Band Gap ◽  
Barrier Height ◽  
Rapid Thermal Annealing ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Reverse Current ◽  
Deep Levels ◽  
Schottky Barriers ◽  
Deep Acceptor ◽  
Transient Spectroscopy

In this paper, the deep levels occurring in Fe- or Co-germanide Schottky barriers on ntype Ge have been studied by Deep Level Transient Spectroscopy (DLTS). As is shown, no traps have been found for germanidation temperatures up to 500 oC, suggesting that in both cases no marked metal in-diffusion takes place during the Rapid Thermal Annealing (RTA) step. Deep acceptor states in the upper half of the Ge band gap and belonging to substitutional Co and Fe can be detected by DLTS only at higher RTA temperatures (TRTA). For the highest TRTA, deep levels belonging to other metal contaminants (Cu) have been observed as well. Simultaneously, the reverse current of the Schottky barriers increases with TRTA, while the barrier height is also strongly affected.

Effects of Sacrifice Oxidation on Characterization of Defects in High-Purity Semi-Insulating 4H-SiC by Discharge Current Transient Spectroscopy

2012 ◽  
Vol 717-720 ◽  
pp. 271-274
Author(s):  
Seiji Nishikawa ◽  
Ryota Okada ◽  
Hideharu Matsuura
Keyword(s):  
Discharge Current ◽  
High Purity ◽  
Deep Level ◽  
Energy Levels ◽  
Reverse Current ◽  
Current Transient ◽  
Emission Rates ◽  
Transient Spectroscopy ◽  
Capacitance Transient ◽  
Surface Leakage

To determine the energy levels of intrinsic defects in high-purity semi-insulating 4H-SiC, we apply discharge current transient spectroscopy (DCTS) that is a graphical peak analysis method based on the transient reverse current of a Schottky barrier diode, because transient capacitance methods such as deep level transient spectroscopy and isothermal capacitance transient spectroscopy are feasible only in low-resistivity semiconductors. The reverse current consists the reverse current through the balk and the surface leakage current of the diode. It is elucidated that the sacrifice oxidation could dramatically reduce the surface currents of diodes in the case of high-purity semi-insulating 4H-SiC, suggesting that the densities and emission rates of traps in the bulk of the SiC can be determined from the transient reverse current.

Determination of Intrinsic Defects in High-Purity Semi-Insulating 4H-SiC by Discharge Current Transient Spectroscopy

2009 ◽  
Vol 615-617 ◽  
pp. 385-388 ◽  
Author(s):  
Hideharu Matsuura ◽  
Miyuki Takahashi ◽  
Yoshitaka Kagawa ◽  
Shoichi Tano ◽  
Takayuki Miyake
Keyword(s):  
Discharge Current ◽  
High Purity ◽  
Deep Level ◽  
Energy Levels ◽  
Reverse Current ◽  
Current Transient ◽  
Intrinsic Defect ◽  
Intrinsic Defects ◽  
Transient Spectroscopy ◽  
Capacitance Transient

To determine the energy levels of intrinsic defects in high-purity semi-insulating 4H-SiC, we apply discharge current transient spectroscopy (DCTS) that is a graphical peak analysis method based on the transient reverse current of a Schottky barrier diode, because transient capacitance methods such as deep level transient spectroscopy and isothermal capacitance transient spectroscopy are feasible only in low-resistivity semiconductors. Seven intrinsic defects are detected in the high-purity semi-insulating 4H-SiC. From the temperature dependence of the emission rate of each intrinsic defect, its activation energy is approximately determined.

Electrical Characterization of Proton Irradiated n-Type ZnO

2006 ◽  
Vol 957 ◽  
Author(s):  
F Danie Auret ◽  
Michael Hayes ◽  
Jackie Nel ◽  
Walter Meyer ◽  
Pieter Johan Janse van Rensburg ◽  
...  
Keyword(s):  
Conduction Band ◽  
Deep Level Transient Spectroscopy ◽  
Proton Irradiation ◽  
Deep Level ◽  
Electrical Characterization ◽  
Low Concentrations ◽  
Transient Spectroscopy ◽  
Induced Defects ◽  
Irradiation Induced Defects

ABSTRACTRu Schottky barrier diodes (SBD's) were fabricated on the Zn face of n-type ZnO. These diodes were irradiated with 1.8 MeV at fluences ranging from 1 ´ 1013 cm-2 to 2.4 ´ 1014 cm-2. Capacitance and current (I) deep level transient spectroscopy (DLTS) was used to characterise the irradiation induced defects. Capacitance DLTS showed that proton irradiation introduced a level, Ep1, at 0.52 eV below the conduction band at an introduction rate of 13±1 cm-1. A defect with a very similar DLTS signature was also present in low concentrations in unirradiated ZnO. I-DLTS revealed that this proton irradiation introduced a defect with an energy level at (0.036± 0.004) eV below the conduction band. This defect is clearly distinguishable from a defect with a level at (0.033± 0.004) eV below the conduction band that was present in the unirradiated sample. It is speculated that these shallow level defects are related to zinc interstitials or complexes involving them.

scholarly journals Correlation between Defects and Electrical Performances of Ion-Irradiated 4H-SiC p–n Junctions

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1966
Author(s):  
Domenico Pellegrino ◽  
Lucia Calcagno ◽  
Massimo Zimbone ◽  
Salvatore Di Franco ◽  
Antonella Sciuto
Keyword(s):  
Deep Level ◽  
Electrical Characterization ◽  
High Fluence ◽  
Defect States ◽  
Exponential Parameter ◽  
Current Voltage ◽  
Different Temperatures ◽  
In Series ◽  
Transient Spectroscopy ◽  
Fluence Range

In this study, 4H-SiC p–n junctions were irradiated with 700 keV He+ ions in the fluence range 1.0 × 1012 to 1.0 × 1015 ions/cm2. The effects of irradiation were investigated by current–voltage (I–V) and capacitance–voltage (C–V) measurements, while deep-level transient spectroscopy (DLTS) was used to study the traps introduced by irradiation defects. Modifications of the device’s electrical performances were observed after irradiation, and two fluence regimes were identified. In the low fluence range (≤1013 ions/cm2), I–V characteristics evidenced an increase in series resistance, which can be associated with the decrease in the dopant concentration, as also denoted by C–V measurements. In addition, the pre-exponential parameter of junction generation current increased with fluence due to the increase in point defect concentration. The main produced defect states were the Z1/2, RD1/2, and EH6/7 centers, whose concentrations increased with fluence. At high fluence (>1013 ions/cm2), I–V curves showed a strong decrease in the generation current, while DLTS evidenced a rearrangement of defects. The detailed electrical characterization of the p–n junction performed at different temperatures highlights the existence of conduction paths with peculiar electrical properties introduced by high fluence irradiation. The results suggest the formation of localized highly resistive regions (realized by agglomeration of point defects) in parallel with the main junction.

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