Radiation Defects Produced in 4H-SiC Epilayers by Proton and Alpha-Particle Irradiation

2013 ◽  
Vol 740-742 ◽  
pp. 661-664 ◽  
Author(s):  
Pavel Hazdra ◽  
Vít Záhlava ◽  
Jan Vobecký ◽  
Maxime Berthou ◽  
Andrei Mihaila
Keyword(s):  
Alpha Particle ◽  
Deep Level ◽  
Schottky Diodes ◽  
Radiation Defects ◽  
Power Diodes ◽  
Projected Range ◽  
Particle Irradiation ◽  
Transient Spectroscopy ◽  
State Resistance ◽  
Low Irradiation

Electronic properties of radiation damage produced in 4H-SiC epilayer by proton and alpha particle irradiation were investigated and compared. 4H-SiC epilayers, which formed the low doped n-base of Schottky barrier power diodes, were irradiated to identical depth with 550 keV protons and 1.9 MeV alphas. Radiation defects were then characterized by capacitance deep-level transient spectroscopy and C-V measurements. Results show that both projectiles produce identical, strongly localized damage peaking at ion’s projected range. Radiation defects have a negligible effect on dynamic characteristic of irradiated 4H-SiC Schottky diodes, however acceptor character of introduced deep levels and their high introduction rates deteriorate diode’s ON-state resistance already at very low irradiation fluences.

Point Defects in 4H-SiC Epilayers Introduced by 4.5 MeV Electron Irradiation and their Effect on Power JBS SiC Diode Characteristics

2013 ◽  
Vol 205-206 ◽  
pp. 451-456 ◽  
Author(s):  
Pavel Hazdra ◽  
Vít Záhlava ◽  
Jan Vobecký
Keyword(s):  
Electron Irradiation ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Radiation Defects ◽  
Electrical Parameters ◽  
Power Diodes ◽  
Defect Centers ◽  
Measurement Results ◽  
Transient Spectroscopy ◽  
State Resistance

Electronic properties of radiation damage produced in 4H-SiC by electron irradiation and its effect on electrical parameters of Junction Barrier Schottky (JBS) diodes were investigated. 4H‑SiC N‑epilayers, which formed the low‑doped N-base of JBS power diodes, were irradiated with 4.5 MeV electrons with fluences ranging from 1.5x1014 to 5x1015 cm-2. Radiation defects were then characterized by capacitance deep-level transient spectroscopy and C-V measurement. Results show that electron irradiation introduces two defect centers giving rise to acceptor levels at EC‑0.39 and EC‑0.60 eV. Introduction rate of these centers is 0.24 and 0.65 cm‑1, respectively. These radiation defects have a negligible effect on blocking and dynamic characteristics of irradiated diodes, however, the acceptor character of introduced deep levels and their high introduction rates deteriorate diode’s ON-state resistance already at fluences higher than 1x1015 cm‑2.

Evaluation of On-State Resistance and Boron-Related Levels in n-Type 4H-SiC

2005 ◽  
Vol 483-485 ◽  
pp. 425-428 ◽  
Author(s):  
R.R Ciechonski ◽  
Samuele Porro ◽  
Mikael Syväjärvi ◽  
Rositza Yakimova
Keyword(s):  
Minority Carrier ◽  
Deep Level ◽  
Schottky Diodes ◽  
Depth Profiling ◽  
Thermionic Emission ◽  
Barrier Heights ◽  
Transient Spectroscopy ◽  
State Resistance ◽  
Thick Layers

Specific on-resistance Ron estimated from current density-voltage characteristics of Schottky diodes on thick layers exhibits variations from tens of mW.cm2 to tens of W.cm2 for different doping levels. In order to understand the occurrence of high on-state resistance, Schottky barrier heights were first estimated for both forward and reverse bias with the application of thermionic emission theory and were in agreement with a literature reported values. Decrease in mobility with the temperature was observed and its dependencies of T–1.3 and T–2.0 for moderately doped and low doped samples respectively were estimated. From deep level measurements by Minority Carrier Transient Spectroscopy, an influence of shallow boron related levels and D-center on dependence of on-state resistance was observed, being more pronounced in low doped samples. Similar tendency was observed in depth profiling of Ron. This suggests a major role of boron in a compensation mechanism thus resulting in high Ron.

Characterization and Simulation of Neutron Irradiated JBS Silicon Carbide Diode Structures

2014 ◽  
Vol 605 ◽  
pp. 151-154
Author(s):  
Stanislav Popelka ◽  
Pavel Hazdra ◽  
Vít Záhlava
Keyword(s):  
Radiation Damage ◽  
Nuclear Reactor ◽  
Deep Level ◽  
Free Charge Carrier ◽  
Deep Levels ◽  
Fast Neutrons ◽  
Precise Analysis ◽  
Transient Spectroscopy ◽  
State Resistance ◽  
Low Irradiation

The effect of radiation damage produced by fast neutrons on characteristics of JBS diodes produced on 4HSiC epilayers was investigated. 1200V JBS diodes from Cree were irradiated in nuclear reactor by fast neutrons with fluences ranging from 1.3x1013to 4x1014cm-2(1MeV NIEL equivalent in Si). Evolution of radiation damage was studied by deep level transient spectroscopy. New characterization method based on dynamic measurement of current to voltage characteristics in the kV range then allowed precise analysis of blocking characteristics and observation of free charge carrier removal with increasing neutron fluence. Results show that irradiation with fast neutrons introduces different point defect giving rise to acceptor like deep levels in SiC bandgap. These levels have a negligible effect on dynamic and blocking characteristics of irradiated JBS diodes, however, acceptor character of introduced deep levels accompanied by deactivation of donor dopants deteriorates diodes ON-state resistance already at low irradiation fluences. This degradation is then manifested by increasing values of the series resistance and the emission coefficient in the SPICE model of the JBS diode.

Deep level defects and carrier removal due to proton and alpha particle irradiation of InP

1994 ◽  
Vol 75 (6) ◽  
pp. 3187-3189 ◽  
Author(s):  
George C. Rybicki ◽  
Christian A. Zorman
Keyword(s):  
Alpha Particle ◽  
Deep Level ◽  
Particle Irradiation

scholarly journals Deep levels in n-type Schottky and p+-n homojunction GaN diodes

2000 ◽  
Vol 5 (S1) ◽  
pp. 922-928
Author(s):  
A. Hierro ◽  
D. Kwon ◽  
S. A. Ringel ◽  
M. Hansen ◽  
U. K. Mishra ◽  
...  
Keyword(s):  
Deep Level Transient Spectroscopy ◽  
Minority Carrier ◽  
Deep Level ◽  
Schottky Diodes ◽  
Yellow Luminescence ◽  
Arrhenius Behavior ◽  
Electron Level ◽  
Transient Spectroscopy ◽  
Electron And Hole Traps

The deep level spectra in both p+-n homojunction and n-type Schottky GaN diodes are studied by deep level transient spectroscopy (DLTS) in order to compare the role of the junction configuration on the defects found within the n-GaN layer. Both majority and minority carrier DLTS measurements are performed on the diodes allowing the observation of both electron and hole traps in n-GaN. An electron level at Ec−Et=0.58 and 0.62 V is observed in the p+-n and Schottky diodes, respectively, with a concentration of ∼3−4×1014 cm−3 and a capture cross section of ∼1−5×10−15 cm2. The similar Arrhenius behavior indicates that both emissions are related to the same defect. The shift in activation energy is correlated to the electric field enhanced-emission in the p+-n diode, where the junction barrier is much larger. The p+-n diode configuration allows the observation of a hole trap at Et−Ev=0.87 eV in the n-GaN which is very likely related to the yellow luminescence band.

“Recovery” Effect of Electron Induced Damage in 4H-SiC Schottky Diodes

2003 ◽  
Vol 792 ◽  
Author(s):  
A. Castaldini ◽  
A. Cavallini ◽  
L. Rigutti ◽  
F. Nava ◽  
P.G. Fuochi ◽  
...  
Keyword(s):  
Deep Level ◽  
Collection Efficiency ◽  
Schottky Diodes ◽  
Chemical Vapour ◽  
Liquid Nitrogen Temperature ◽  
Charge Collection Efficiency ◽  
Before And After ◽  
Transient Spectroscopy ◽  
Lower Temperature ◽  
Different Doses

ABSTRACTThe effects of electron irradiation on the defects associated electronic levels in Schottky diodes on 4H silicon carbide epilayers grown by chemical vapour deposition were investigated by Deep Level Transient Spectroscopy (DLTS) and Capacitance-Voltage (C-V) characteristics. These investigations were performed before and after irradiation with 8.6 MeV electrons at different doses. After irradiation four new traps with enthalpies equal to (Ec-0.23 eV), (Ec-0.39 eV), (Ec-0.63 eV) and (Ec-0.75 eV) were detected. Their thermal stability, a key point to determine their structure on the basis of recent theoretical and experimental results, was carefully investigated since it was earlier observed that during DLTS temperature runs up to 500 K a slight but significant recovery of a few irradiation-induced levels occurs. This effect was previously observed in literature for the level (Ec-0.70 eV) after thermal treatment at 500 °C [1], but the present results indicate that it involves more than a single level and is also effective at lower temperature. DLTS analyses were also performed from room temperature to liquid nitrogen temperature and vice versa up to 500 K.The annealing kinetics is reported and a few conclusions on the structure of the defects involved in the recovery are drawn. The correlation with the diode charge collection efficiency is also reported.

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.

Space Radiation Effects in Advanced Solar Cell Materials and Devices

2001 ◽  
Vol 692 ◽  
Author(s):  
R. J. Walters ◽  
G. P. Summers
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Radiation Effects ◽  
Deep Level ◽  
Spectral Response ◽  
Cell Structure ◽  
Electrical Performance ◽  
Internal Cell ◽  
Particle Irradiation ◽  
Transient Spectroscopy

AbstractAn investigation of the physical mechanisms governing the response of III-V based solar cells to particle irradiation is presented. The effect of particle irradiation on single and multijunction solar cells is studied through current vs. voltage, spectral response, and deep level transient spectroscopy measurements. The basic radiation response mechanisms are identified, and their effects on the solar cell electrical performance are described. In particular, a detailed analysis of multijunction InxGa1-xP/InyGa1-yAs/Ge devices is presented. The MJ cell response is found to be more strongly affected by the internal cell structure than by the In content.

Correlation between Leakage Current and Ion-Irradiation Induced Defects in 4H-SiC Schottky Diodes

2006 ◽  
Vol 527-529 ◽  
pp. 1167-1170 ◽  
Author(s):  
Vito Raineri ◽  
Fabrizio Roccaforte ◽  
Sebania Libertino ◽  
Alfonso Ruggiero ◽  
V. Massimino ◽  
...  
Keyword(s):  
Leakage Current ◽  
Ion Irradiation ◽  
Deep Level ◽  
Schottky Diodes ◽  
Arrhenius Dependence ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Transient Spectroscopy ◽  
Induced Defects ◽  
Irradiation Induced Defects

The defects formation in ion-irradiated 4H-SiC was investigated and correlated with the electrical properties of Schottky diodes. The diodes were irradiated with 1 MeV Si+-ions, at fluences ranging between 1×109cm-2 and 1.8×1013cm-2. After irradiation, the current-voltage characteristics of the diodes showed an increase of the leakage current with increasing ion fluence. The reverse I-V characteristics of the irradiated diodes monitored as a function of the temperature showed an Arrhenius dependence of the leakage, with an activation energy of 0.64 eV. Deep level transient spectroscopy (DLTS) allowed to demonstrate that the Z1/Z2 center of 4H-SiC is the dominant defect in the increase of the leakage current in the irradiated material.

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