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

2007 ◽  
Vol 556-557 ◽  
pp. 359-362 ◽  
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.

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

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

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

2012 ◽  
Vol 717-720 ◽  
pp. 305-308 ◽  
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.

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

2007 ◽  
Vol 46 (8A) ◽  
pp. 5057-5061 ◽  
Author(s):  
Masashi Kato ◽  
Masahiko Kawai ◽  
Tatsuhiro Mori ◽  
Masaya Ichimura ◽  
Shingo Sumie ◽  
...  
Keyword(s):  
Carrier Lifetime ◽  
Excess Carrier ◽  
Photoconductivity Decay ◽  
P Type ◽  
Sic Wafer

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

2010 ◽  
Vol 645-648 ◽  
pp. 207-210 ◽  
Author(s):  
Yoshinori Matsushita ◽  
Masashi Kato ◽  
Masaya Ichimura ◽  
Tomoaki Hatayama ◽  
Takeshi Ohshima
Keyword(s):  
Cross Sections ◽  
Carrier Lifetime ◽  
Excitation Density ◽  
Excess Carrier ◽  
Carrier Lifetimes ◽  
Photoconductivity Decay ◽  
Recombination Centers ◽  
P Type ◽  
Capture Cross Sections

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.

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

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.

Persistent Photoconductivity in p-Type 4H-SiC Bulk Crystals

2013 ◽  
Vol 740-742 ◽  
pp. 413-416 ◽  
Author(s):  
Takafumi Okuda ◽  
Hiroki Miyake ◽  
Tsunenobu Kimoto ◽  
Jun Suda
Keyword(s):  
Decay Time ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Persistent Photoconductivity ◽  
Bulk Crystals ◽  
Decay Times ◽  
Photoconductivity Decay ◽  
Increasing Temperature ◽  
P Type ◽  
Homoepitaxial Layers

We investigated the photoconductivity decay characteristics of p-type 4H-SiC bulk crystals grown by a modified Lely method by differential microwave photoconductance decay (μ-PCD) measurements using a 349-nm laser as an excitation source. We observed persistent photoconductivity (PPC) in the p-type SiC bulk crystals. The decay time at room temperature was 2600 μs. The decay time decreased with increasing temperature, resulting in 120 μs at 250oC, and the activation energy of the decay times was determined to be 140±10 meV. Long decay characteristics were also observed by below-band-gap excitation at 523 or 1047 nm. On the other hand, no PPC was observed in p-type homoepitaxial layers grown by hot-wall chemical vapor deposition.

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

2009 ◽  
Vol 615-617 ◽  
pp. 295-298 ◽  
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.

Influence of Epilayer Thickness and Structural Defects on the Minority Carrier Lifetime in 4H-SiC

2013 ◽  
Vol 740-742 ◽  
pp. 633-636 ◽  
Author(s):  
Birgit Kallinger ◽  
Patrick Berwian ◽  
Jochen Friedrich ◽  
Mathias Rommel ◽  
Maral Azizi ◽  
...  
Keyword(s):  
Carrier Lifetime ◽  
Minority Carrier ◽  
Deep Level ◽  
Surface Recombination ◽  
Minority Carrier Lifetime ◽  
Structural Defects ◽  
Effective Lifetime ◽  
Recombination Lifetime ◽  
Photoconductivity Decay ◽  
Transient Spectroscopy

4H-SiC homoepitaxial layers with different thicknesses from 12.5 µm up to 50 µm were investigated by microwave-detected photoconductivity decay (µ-PCD), deep level transient spectroscopy (DLTS) and defect selective etching (DSE) to shed light on the influence of the epilayer thickness and structural defects on the effective minority carrier lifetime. It is shown that the effective lifetime, resulting directly from the µ-PCD measurement, is significantly influenced by the surface recombination lifetime. Therefore, an adequate correction of the measured data is necessary to determine the bulk lifetime. The bulk lifetime of these epilayers is in the order of several microseconds. Furthermore, areas with high dislocation density are correlated to areas with locally reduced effective lifetime.

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