Defects in an Electron-Irradiated 6H-SiC Diode Studied by Alpha Particle Induced Charge Transient Spectroscopy: Their Impact on the Degraded Charge Collection Efficiency

2012 ◽  
Vol 717-720 ◽  
pp. 267-270
Author(s):  
Naoya Iwamoto ◽  
Atsushi Koizumi ◽  
Shinobu Onoda ◽  
Takahiro Makino ◽  
Takeshi Ohshima ◽  
...  

Defects in electron-irradiated 6H-SiC diodes have been studied by single alpha particle induced charge transient spectroscopy and deep level transient spectroscopy (DLTS) in order to identify critical defects responsible for the charge collection efficiency (CCE) decreased by high-energy electron irradiation. The defect X2 detected by the charge transient spectroscopy and the electron trap Ei detected by the DLTS had a similar activation energy of around 0.50 eV. In addition, the annealing at 200oC completely removed defects X2 and Ei, and restored the CCE. The defect X2 is attributed to the electron trap Ei, and responsible for the decreased CCE.

2006 ◽  
Vol 911 ◽  
Author(s):  
Anna Cavallini ◽  
Antonio Castaldini ◽  
Filippo Nava ◽  
Paolo Errani ◽  
Vladimir Cindro

AbstractWe investigated the electronic levels of defects introduced in 4H-SiC α-particle detectors by irradiation with 1 MeV neutrons up to a fluence equal to 8x1015 n/cm2. As well, we investigated their effect on the detector radiation hardness. This study was carried out by deep level transient spectroscopy (DLTS) and photo-induced current transient spectroscopy (PICTS). As the irradiation level approaches fluences in the order of 1015 n/cm2, the material behaves as highly resistive due to a very great compensation effect but the diodes are still able to detect with a acceptably good charge collection efficiency (CCE) equal to 80%. By further increasing fluence, CCE decreases reaching the value of ≈ 20% at fluence of 8x1015 n/cm2.The dominant peaks in the PICTS spectra occur in the temperature range [400, 700] K. Enthalpy, capture cross-section and order of magnitude of the density of such deep levels were calculated. In the above said temperature range the deep levels associated to the radiation induced defects play the key role in the degradation of the CCE. Two deep levels at Et = 1.18 eV and Et = 1.50 eV are likely to be responsible of such dramatic decrease of the charge collection efficiency. These levels were reasonably associated to an elementary defect involving a carbon vacancy and to a defect complex involving a carbon and a silicon vacancy, respectively.


1996 ◽  
Vol 35 (Part 1, No. 2B) ◽  
pp. 869-873 ◽  
Author(s):  
Tomohiro Yamashita ◽  
Shigeki Komori ◽  
Takashi Kuroi ◽  
Masahide Inuishi ◽  
Hirokazu Miyoshi

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5107 ◽  
Author(s):  
Sandupatla ◽  
Arulkumaran ◽  
Ranjan ◽  
Ing ◽  
Murmu ◽  
...  

A low voltage (–20 V) operating high-energy (5.48 MeV) α-particle detector with a high charge collection efficiency (CCE) of approximately 65% was observed from the compensated (7.7 × 1014 /cm3) metalorganic vapor phase epitaxy (MOVPE) grown 15 µm thick drift layer gallium nitride (GaN) Schottky diodes on free-standing n+-GaN substrate. The observed CCE was 30% higher than the bulk GaN (400 µm)-based Schottky barrier diodes (SBD) at –20 V. This is the first report of α–particle detection at 5.48 MeV with a high CCE at –20 V operation. In addition, the detectors also exhibited a three-times smaller variation in CCE (0.12 %/V) with a change in bias conditions from –120 V to –20 V. The dramatic reduction in CCE variation with voltage and improved CCE was a result of the reduced charge carrier density (CCD) due to the compensation by Mg in the grown drift layer (DL), which resulted in the increased depletion width (DW) of the fabricated GaN SBDs. The SBDs also reached a CCE of approximately 96.7% at –300 V.


2003 ◽  
Vol 792 ◽  
Author(s):  
A. Castaldini ◽  
A. Cavallini ◽  
L. Rigutti ◽  
F. Nava ◽  
P.G. Fuochi ◽  
...  

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.


2019 ◽  
Author(s):  
Nirmalya Basu

Induced charge errors lead to underestimation of transferred charge in brush discharges when the measurement is done using fast-response unshielded probes. The discrepancy observed between the values of charge-collection efficiency for different charge-transfer thresholds obtained theoretically by Walmsley [2] and those obtained experimentally by Chowdhury et al [3] necessitates figuring out ways to improve the mathematical model used by Walmsley. A close perusal of the said work by Walmsley [2] has pointed out an error therein– in the use of the equation reff = KD. I propose here a way to get rid of this error, and in doing so, I propose a method of calculating the charge-collection efficiency in charge-transfer measurement for brush discharges more reliable than that used by Walmsley [2].


2021 ◽  
pp. 43-50
Author(s):  
A.I. Kondrik

The work is dedicated to studying by computer modeling the mechanisms of the influence of radiation defects, originating under high energy proton irradiation, on the resistivity ρ, lifetime of nonequilibrium electrons n and holes p in CdTe:Cl and Cd0.9Zn0.1Te, and charge collection efficiency η of room temperature ionizing radiation detectors based on these materials. The effect of recombination at deep levels of radiation defects on the degradation of n, p, and  of detectors based on CdTe:Cl and Cd0.9Zn0.1Te was studied. Energy levels of radiation defects also substantially effect on compensation degree of semiconductor decreasing ρ. The main factors affecting the abrupt or gradual decrease in the resistivity and charge collection efficiency of these detectors during their bombardment by high-energy protons, leading to complete degradation of their recording ability, were found. The important role of purity and deep donor concentration in initial state of the detector material was indicated.


2011 ◽  
Vol 58 (6) ◽  
pp. 3328-3332 ◽  
Author(s):  
Naoya Iwamoto ◽  
Atsushi Koizumi ◽  
Shinobu Onoda ◽  
Takahiro Makino ◽  
Takeshi Ohshima ◽  
...  

2002 ◽  
Vol 16 (06n07) ◽  
pp. 1018-1023 ◽  
Author(s):  
J. AHN ◽  
B. GAN ◽  
Q. ZHANG ◽  
S. F. YOON ◽  
V. LIGATCHEV ◽  
...  

The CVD diamond UV photodetector shows more than four orders of photoresponsivity discrimination between UV and visible light. Post-treatment on as-fabricated photodetector is essential for a good response to UV light and blindness to visible light. The CVD diamond X-ray detector shows linear dependence of photocurrent on X-ray intensity and high response speed. The mapping of charge collection efficiency on the whole sensing area of a CVD diamond alpha particle detector has been obtained using ion-beam-induced charge microscopy technique. Three peaks have been observed in the charge collection spectrum.


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