Impacts of recombination at the surface and in the substrate on carrier lifetimes of n-type 4H–SiC epilayers

Kimoto, Tsunenobu; Hiyoshi, Toru; Hayashi, Toshihiko; Suda, Jun

doi:10.1063/1.3498818

Cited by 79 publications

(81 citation statements)

References 36 publications

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“…A carrier lifetime of 8.2 µs, which may be compared with 3C-SiC grown on silicon in which the carrier lifetime is ranging from a few to 120 nanoseconds, was reported [12]. The typical lifetime in as-grown 4H-SiC is around 1 μs under the low injection level, while higher values was reported to be enhanced from 0.69 to 9.5 μs after thermal treatment [13] or from 3.5 to 18-19 µs post carbon-implantation and annealing [14]. Thus a growth process that reproducibly maintains such quality could open up 3C-SiC for electronic and optoelectronic devices.…”

Section: Resultsmentioning

confidence: 99%

Cubic silicon carbide as a potential photovoltaic material

Syväjärvi

Jokubavičius

et al. 2016

Solar Energy Materials and Solar Cells

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In this work we present a significant advancement in cubic silicon carbide (3C-SiC) growth in terms of crystal quality and domain size, and indicate its potential use in photovoltaics. To date, the use of 3C-SiC for photovoltaics has not been considered due to the band gap of 2.3 eV being too large for conventional solar cells. Doping of 3C-SiC with boron introduces an energy level of 0.7 eV above the valence band. Such energy level may form an intermediate band (IB) in the band gap. This IB concept has been presented in the literature to act as an energy ladder that allows absorption of sub-bandgap photons to generate extra electron-hole pairs and increase the efficiency of a solar cell. The main challenge with this concept is to find a materials system that could realize such efficient photovoltaic behavior. The 3C-SiC bandgap and boron energy level fits nicely into the concept, but has not been explored for an IB behavior.For a long time crystalline 3C-SiC has been challenging to grow due to its metastable nature. The material mainly consists of a large number of small domains if the 3C polytype is maintained. In our work a crystal growth process was realized by a new approach that is a combination of initial nucleation and step-flow growth. In the process, the domains that form initially extend laterally to make larger 3C-SiC domains, thus leading to a pronounced improvement in crystalline quality of 3C-SiC. In order to explore the feasibility of IB in 3C-SiC using boron, we have explored two routes of introducing boron impurities; ion implantation on un-doped samples and epitaxial growth on un-doped samples using pre-doped source material. The results show that 3C-SiC doped with boron is an optically active material, and thus is interesting to be further studied for IB behavior.For the ion implanted samples the crystal quality was maintained even after high implantation doses and subsequent annealing. The same was true for the samples grown with pre-doped source material, even with a high concentration of boron impurities.We present optical emission and absorption properties of as-grown and boron implanted 3C-SiC. The low-temperature photoluminescence spectra indicate the formation of optically active deep boron centers, which may be utilized for achieving an IB behavior at sufficiently high dopant concentrations. We also discuss the potential of boron doped 3C-SiC base material in a broader range of applications, such as in photovoltaics, biomarkers and hydrogen generation by splitting water.

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Section: Resultsmentioning

confidence: 99%

Cubic silicon carbide as a potential photovoltaic material

Syväjärvi

Jokubavičius

et al. 2016

Solar Energy Materials and Solar Cells

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“…This measured carrier lifetime in as-grown 3C-SiC is much higher than the reported values in 3C-SiC grown by other methods, [19][20][21] even a little bit higher than the typical values in as-grown 4H-SiC. [11][12][13][14][15] The maximum carrier lifetime reported in asgrown 4H-SiC is 8.6 ls, 11 which was measured by l-PCD in a high-quality 50 lm thick CVD epilayer under an injection of 5 Â 10 12 cm À2 . The measured conditions are quite similar to our measurements.…”

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confidence: 39%

“…[11][12][13][14] Recently, it was shown that the reduction of the defects of Z 1/2 and EH 6/7 by post-growth processes results in an improvement of carrier lifetime. Kimoto et al 15 reported that the carrier lifetime in a 148-lm-thick 4H-SiC layer is enhanced from 0.69 to 9.5 ls after thermal treatment. Miyazawa et al 17 showed that using post carbon-implantation and annealing, the carrier lifetime in 4H-SiC was improved from 3.5 ls to an extraordinarily long value of 18-19 ls.…”

mentioning

confidence: 99%

“…The typical lifetime in as-grown 4H-SiC is around 1 ls under the low injection level. [11][12][13][14][15][16] The main lifetime-limiting defects are recognized as Z 1/2 and EH 6/7 centers, which are related to intrinsic defects with energy levels located at 0.65 eV and 1.55 eV below the conduction band, respectively. [11][12][13][14] Recently, it was shown that the reduction of the defects of Z 1/2 and EH 6/7 by post-growth processes results in an improvement of carrier lifetime.…”

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Considerably long carrier lifetimes in high-quality 3C-SiC(111)

Sun

Ivanov

Liljedahl

et al. 2012

Applied Physics Letters

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As a challenge and consequence due to its metastable nature, cubic silicon carbide (3C-SiC) has only shown inferior material quality compared with the established hexagonal polytypes. We report on growth of 3C-SiC(111) having a state of the art semiconductor quality in the SiC polytype family. The x-ray diffraction and low temperature photoluminescence measurements show that the cubic structure can indeed reach a very high crystal quality. As an ultimate device property, this material demonstrates a measured carrier lifetime of 8.2 mu s which is comparable with the best carrier lifetime in 4 H-SiC layers. In a 760-mu m thick layer, we show that the interface recombination can be neglected since almost all excess carriers recombines before reaching the interface while the surface recombination significantly reduces the carrier lifetime. In fact, a comparison of experimental lifetimes with numerical simulations indicates that the real bulk lifetime in such high quality 3C-SiC is in the range of 10-15 mu s

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“…The second factor is the lack of drift/diffusion and surface recombination in the simulation, which would reduce the effective simulated lifetime up to several times for high lifetime samples. 21 None of these factors however would change the shown trend for samples from cells S1, S2 and C2. all samples and their measured lifetimes (and slightly below that of highest lifetime samples grown in cell S1), RB1 appears in large concentrations with a trend anti-proportional to τ meas and is the dominant recombination center in low-lifetime samples.…”

Section: Resultsmentioning

confidence: 99%

Carrier Lifetime Controlling Defects Z_1/2 and RB1 in Standard and Chlorinated Chemistry Grown 4H-SiC

Booker

Ul-Hassan

Lilja

et al. 2014

Crystal Growth & Design

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4H-SiC epilayers grown by standard and chloride based chemistry were analyzed for their minority carrier lifetime and deep level recombination centers using time resolved photoluminescence (TRPL) and standard and p + /n-junction deep level transient spectroscopy (DLTS). Next to the wellknown Z 1/2 deep level a second effective lifetime killer, RB1 is detected in chloride chemistry grown epilayers. The measured RB1 concentration appears to be a function of the iron-related Fe1 level concentration, which is introduced via the corrosion of reactor steel parts by the chlorinated chemistry. Reactor design and the temperature profile in the growth zone appear to enable the formation of RB1 in the presence of iron contamination under conditions otherwise optimal for growth of material with very low Z 1/2 concentrations. Control of these corrosion issues allows the growth of material at a significantly higher growth rate than possible using standard chemistry and with high minority carrier lifetime based on Z 1/2 as the only bulk recombination center. or a complex involving iron. Control of these corrosion issues allows the growth of material at a high growth rate and with high minority carrier lifetime based on Z 1/2 as the only bulk recombination center.

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Impacts of recombination at the surface and in the substrate on carrier lifetimes of n-type 4H–SiC epilayers

Cited by 79 publications

References 36 publications

Cubic silicon carbide as a potential photovoltaic material

Cubic silicon carbide as a potential photovoltaic material

Considerably long carrier lifetimes in high-quality 3C-SiC(111)

Carrier Lifetime Controlling Defects Z_1/2 and RB1 in Standard and Chlorinated Chemistry Grown 4H-SiC

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Impacts of recombination at the surface and in the substrate on carrier lifetimes of n-type 4H–SiC epilayers

Cited by 79 publications

References 36 publications

Cubic silicon carbide as a potential photovoltaic material

Cubic silicon carbide as a potential photovoltaic material

Considerably long carrier lifetimes in high-quality 3C-SiC(111)

Carrier Lifetime Controlling Defects Z1/2 and RB1 in Standard and Chlorinated Chemistry Grown 4H-SiC

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Carrier Lifetime Controlling Defects Z_1/2 and RB1 in Standard and Chlorinated Chemistry Grown 4H-SiC