Characterization of the Excess Carrier Lifetime of As-Grown and Electron Irradiated Epitaxial p-Type 4H-SiC Layers by the Microwave Photoconductivity Decay Method

We measured the excess carrier lifetimes in as-grown and electron irradiated p-type 4H-SiC epitaxial layers with the microwave photoconductivity decay (-PCD) method. The carrier lifetime becomes longer with excitation density for the as-grown epilayer. This dependence suggests that e ≥h for the dominant recombination center, where e andh are capture cross sections for electrons and holes, respectively. In contrast, the carrier lifetime does not depend on the excitation density for the sample irradiated with electrons at an energy of 160 keV and a dose of 1×1017 cm-2. This may be due to the fact that recombination centers with e <<h were introduced by the electron irradiation or due to the fact that the acceptor concentration was decreased significantly by the irradiation.

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Excess Carrier Lifetime in a Bulk p-Type 4H–SiC Wafer Measured by the Microwave Photoconductivity Decay Method

Japanese Journal of Applied Physics ◽

10.1143/jjap.46.5057 ◽

2007 ◽

Vol 46 (8A) ◽

pp. 5057-5061 ◽

Cited By ~ 18

Author(s):

Masashi Kato ◽

Masahiko Kawai ◽

Tatsuhiro Mori ◽

Masaya Ichimura ◽

Shingo Sumie ◽

...

Keyword(s):

Carrier Lifetime ◽

Excess Carrier ◽

Photoconductivity Decay ◽

P Type ◽

Sic Wafer

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Excess Carrier Lifetimes in a Bulk p-Type SiC Wafer Measured by the Microwave Photoconductivity Decay Method

Materials Science Forum ◽

10.4028/www.scientific.net/msf.556-557.359 ◽

2007 ◽

Vol 556-557 ◽

pp. 359-362 ◽

Cited By ~ 2

Author(s):

Masahiko Kawai ◽

Tatsuhiro Mori ◽

Masashi Kato ◽

Masaya Ichimura ◽

Shingo Sumie ◽

...

Keyword(s):

Time Constant ◽

Minority Carrier ◽

Slow Component ◽

Structural Defects ◽

Excess Carrier ◽

Carrier Lifetimes ◽

Photoconductivity Decay ◽

Increasing Temperature ◽

P Type ◽

Sic Wafer

We carried out mapping of the excess carrier lifetime for a bulk p-type 4H-SiC wafer by the microwave photoconductivity decay (μ-PCD) method, and we compared the lifetime map with structural defect distribution. Several small regions with short lifetimes compared with surrounding parts are found, and they correspond to regions with high-density structural defects. Excess carrier decay curves for this wafer show a slow component, which originates from minority carrier traps. From temperature dependence of the excess carrier decay curve, we found decrease of the time constant of the slow component with increasing temperature. We compared the activation energy of the time constant with that obtained from the numerical simulation, and concluded that the energy level for the minority carrier trap would be 125 meV from the conduction band.

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Excess Carrier Lifetimes in a Bulk p-Type SiC Wafer Measured by the Microwave Photoconductivity Decay Method

Materials Science Forum - Silicon Carbide and Related Materials 2006 ◽

10.4028/0-87849-442-1.359 ◽

2007 ◽

pp. 359-362

Author(s):

Masahiko Kawai ◽

Tatsuhiro Mori ◽

Masashi Kato ◽

Masaya Ichimura ◽

Shingo Sumie ◽

...

Keyword(s):

Excess Carrier ◽

Carrier Lifetimes ◽

Photoconductivity Decay ◽

P Type ◽

Sic Wafer

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Correlation between Strain and Excess Carrier Lifetime in a 3C-SiC Wafer

Materials Science Forum ◽

10.4028/www.scientific.net/msf.717-720.305 ◽

2012 ◽

Vol 717-720 ◽

pp. 305-308 ◽

Cited By ~ 1

Author(s):

Atsushi Yoshida ◽

Masashi Kato ◽

Masaya Ichimura

Keyword(s):

Raman Spectroscopy ◽

Optical Microscopy ◽

Carrier Lifetime ◽

Structural Defects ◽

Free Standing ◽

Excess Carrier ◽

Carrier Lifetimes ◽

Photoconductivity Decay ◽

Sic Wafer

We obtained excess carrier lifetime maps by the microwave photoconductivity decay (µ-PCD) method in a free-standing n-type 3C-SiC wafer, and then we compared the lifetime maps with distributions of strains and defects observed by the optical microscopy and the Raman spectroscopy. We found that the excess carrier lifetimes are short in a strained region in 3C-SiC, which indicates that structural defects exist around a strained region.

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Excess Carrier Lifetime Measurements for GaN on Sapphire Substrates with Various Doping Concentrations and Surface Conditions by the Microwave Photoconductivity Decay Method

MRS Proceedings ◽

10.1557/proc-831-e3.3 ◽

2004 ◽

Vol 831 ◽

Author(s):

Masashi Kato ◽

Hideki Watanabe ◽

Masaya Ichimura ◽

Eisuke Arai

Keyword(s):

Inductively Coupled Plasma ◽

Carrier Lifetime ◽

Surface Conditions ◽

Excess Carrier ◽

Carrier Lifetimes ◽

Sapphire Substrates ◽

Icp Etching ◽

Photoconductivity Decay ◽

Si Doped ◽

Mg Doped

ABSTRACTWe have measured excess carrier lifetimes in GaN with various doping concentrations and surface conditions by the microwave photoconductivity decay method. GaN samples were grown by metalorganic chemical vapor deposition (MOCVD) without intentional doping and with Si doping or Mg doping on a-face sapphire substrates. By using the microwave photoconductivity decay method, we obtained 1/e excess carrier lifetimes of larger than 50 μs for the Si doped and undoped GaN and of less than 10 μs for the Mg doped GaN. We changed surface conditions for the samples by the inductively coupled plasma (ICP) etching and investigated effects of surface conditions on the carrier recombination behavior. The ICP etching has negligible effects on carrier lifetime in the Si doped GaN. On the other hand, in the undoped GaN, the ICP etching lengthened the carrier lifetime compared with the as-grown sample. On the contrary, the ICP etching shortened the carrier lifetime in the Mg doped GaN. The ICP etching seems to form hole traps and recombination centers at GaN surfaces and thus the carrier lifetime became longer in the undoped GaN and shorter in the Mg doped GaN.

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The Excess Carrier Lifetime in P-Type HgCdTe Measured by Photoconductive Decay

10.1109/eeis.1989.720012 ◽

2005 ◽

Cited By ~ 2

Author(s):

R. Fastow ◽

Y. Nemirovsky

Keyword(s):

Carrier Lifetime ◽

Photoconductive Decay ◽

Excess Carrier ◽

P Type

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Precise Measurements of Transient Excess Carrier Lifetimes in II-VI Films and Superlattices

MRS Proceedings ◽

10.1557/proc-161-217 ◽

1989 ◽

Vol 161 ◽

Author(s):

W. O. Doggett ◽

Michael W. Thelander ◽

J. F. Schetzina

Keyword(s):

Molecular Beam ◽

Statistical Data ◽

Laser Pulses ◽

Statistical Data Analysis ◽

Analysis Techniques ◽

Excess Carrier ◽

Carrier Lifetimes ◽

System A ◽

Transient Photoconductivity ◽

Photoconductivity Decay

ABSTRACTA system has been developed for accurately measuring lifetimes for photo-induced excess current carriers in semiconductors using the transient photoconductivity decay method. The specifications of state-of-the-art equipment, considerations peculiar to the capture of fast transient pulses, and sophisticated statistical data analysis techniques are discussed. Experimental results are presented to demonstrate the capability of the system (a) to measure lifetimes in the 40-ns - 75-µs range for temperatures varying from 77K to 300K with 10% accuracy for single lifetime decays and 30% accuracy for individual effective lifetimes in a multi-component decay, and (b) to use a 300-ns lifetime photoconductor as a detector to measure nanosecond-time-scale structure of laser pulses. The predominant excess carrier lifetimes of HgCdTe samples grown at NCSU by photoassisted molecular beam epitaxy (PAMBE) ranged from 46 ns at 300K to 341 ns at 77K. CdTe samples and CdMnTe-CdTe superlattices exhibited a multi-component decay with the two longest components having effective lifetimes of 26 µs and 4 µs for CdTe and 75 µs and 10 µs for CdMnTe-CdTe. These values were relatively insensitive to temperature variation.

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Photoluminescence Characterization of Carrier Recombination Centers in 4H-SiC Substrates by Utilizing below Gap Excitation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.897.315 ◽

2017 ◽

Vol 897 ◽

pp. 315-318

Author(s):

Keitaro Kondo ◽

Norihiko Kamata ◽

Hiroyuki Yaguchi ◽

Shuhei Yagi ◽

Takeshi Fukuda ◽

...

Keyword(s):

Density Dependence ◽

Intensity Change ◽

Device Performance ◽

Acceptor Pair ◽

Carrier Recombination ◽

Donor Acceptor ◽

Recombination Centers ◽

P Type ◽

Growth Technology

Though the crystal growth technology of SiC is improving steadily, it is still crucial to reduce crystalline defects which act as carrier recombination (CR) centers and deteriorate device performance. We detected CR centers in a p-type 4H-SiC substrate by observing the intensity change of photoluminescence due to the addition of a below-gap excitation (BGE) light of 0.93[eV]. We noticed the temperature and the BGE density dependence of band edge (BE) emission in addition to donor acceptor pair (DAP) emission and discriminated the temperature effect from that of BGE. The BGE density dependence of the PL intensity quenching is different among the BE emission, B0- and C0-lines of the DAP, respectively. It gives us an important clue for understanding CR mechanisms inside the bandgap of SiC.

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Minority Carrier Lifetime Measurements in Specific Epitaxial 4H-SiC Layers by the Microwave Photoconductivity Decay

Materials Science Forum ◽

10.4028/www.scientific.net/msf.615-617.295 ◽

2009 ◽

Vol 615-617 ◽

pp. 295-298 ◽

Cited By ~ 2

Author(s):

Laurent Ottaviani ◽

Olivier Palais ◽

Damien Barakel ◽

Marcel Pasquinelli

Keyword(s):

Absorption Spectra ◽

Carrier Lifetime ◽

Minority Carrier ◽

Optical Excitation ◽

Minority Carrier Lifetime ◽

Lifetime Measurements ◽

Recombination Processes ◽

Photoconductivity Decay ◽

P Type ◽

Non Destructive

We report on measurements of the minority carrier lifetime for different epitaxial 4H-SiC layers by using the microwave photoconductivity decay (µ-PCD) method. This is a non-contacting, non-destructive method very useful for the monitoring of recombination processes in semiconductor material. Distinct samples have been analyzed, giving different lifetime values. Transmittance and absorption spectra have also been carried out. The n-type layers, giving rise to a specific absorption peak near 470 nm, are not sensitive to optical excitation for the used wavelengths, as opposite to p-type layers whose lifetime values depend on thickness and doping.

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