Hydrogen diffusion, complex formation, and dissociation in acceptor-doped silicon carbide

Janson, Martin S.; Hallén, Anders; Linnarsson, Margareta K.; Svensson, B. G.

doi:10.1103/physrevb.64.195202

Cited by 57 publications

(43 citation statements)

References 28 publications

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“…with a thermal activation energy of E a ¼ 2:0 eV and a prefactor of R 0 ¼ 1:5 Â 10 13 s À1 , which is in good agreement with the lattice vibration frequency for 4H-SiC at 300 C, 30 and thus the annealing out was assigned to a defect dissociation process.…”

Section: B Annealing Of M-center and Generation Of Eb-centerssupporting

confidence: 75%

“…The prefactor will be even more affected by error, thus one order of magnitude more or less can be assumed. The measured R 0 ðEB À centersÞ is thus comparable to R 0 ðM À centerÞ, which was in the range of the calculated vibration frequency of SiC 30 at 300 C, m ¼ 1:6 Â 10 13 s À1 and which is close to the prefactor typical for atomic jump processes. 31 The DLTS amplitudes of the M-center and thus the defect concentration is much higher than the one of the EB-centers, thus only a small amount of the M-center may be transferred to the EB-centers.…”

supporting

confidence: 70%

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Annealing behavior of the EB-centers and M-center in low-energy electron irradiated n-type 4H-SiC

Beyer

Hemmingsson

Pedersen

et al. 2011

Journal of Applied Physics

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After low-energy electron irradiation of epitaxial n-type 4H-SiC with a dose of 5 Â 10 16 cm À2 , the bistable M-center, previously reported in high-energy proton implanted 4H-SiC, is detected in the deep level transient spectroscopy (DLTS) spectrum. The annealing behavior of the M-center is confirmed, and an enhanced recombination process is suggested. The annihilation process is coincidental with the evolvement of the bistable EB-centers in the low temperature range of the DLTS spectrum. The annealing energy of the M-center is similar to the generation energy of the EB-centers, thus partial transformation of the M-center to the EB-centers is suggested. The EB-centers completely disappeared after annealing temperatures higher than 700 C without the formation of new defects in the observed DLTS scanning range. The threshold energy for moving Si atom in SiC is higher than the applied irradiation energy, and the annihilation temperatures are relatively low, therefore the M-center, EH1 and EH3, as well as the EB-centers are attributed to defects related to the C atom in SiC, most probably to carbon interstitials and their complexes.

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Section: B Annealing Of M-center and Generation Of Eb-centerssupporting

confidence: 75%

supporting

confidence: 70%

Annealing behavior of the EB-centers and M-center in low-energy electron irradiated n-type 4H-SiC

Beyer

Hemmingsson

Pedersen

et al. 2011

Journal of Applied Physics

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“…Janson and co-workers [47] conducted ion-implantation experiments to acquire low-velocity electronic stopping power for 1 H and 2 H ions using time-of-flight (TOF) techniques. The experimental data shown in Figure 1.…”

Section: Resultsmentioning

confidence: 99%

“…The dashed black curve represents a dielectric formalism calculation with an empirically fitted dielectric function [48]. Red circles and blue squares show experimental data for protons and deuterium ions, respectively [47]. The pink curve represents results from the dielectric response formalism using LR-TDDFT for calculating the dielectric matrix [26].…”

Section: Theoretical Methodsmentioning

confidence: 99%

Electronic stopping for protons andαparticles from first-principles electron dynamics: The case of silicon carbide

Yost

Kanai

2016

Phys. Rev. B

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We present the first-principles determination of electronic stopping power for protons and α-particles in a semiconductor material of great technological interest: silicon carbide. The calculations are based on non-equilibrium simulations of the electronic response to swift ions using real-time time-dependent density functional theory (RT-TDDFT). We compare the results from this first-principles approach to those of the widely used linear response formalism and determine the ion velocity regime within which linear response treatments are appropriate. We also use the non-equilibrium electron densities in our simulations to quantitatively address the long-standing question of the velocity-dependent effective charge state of projectile ions in a material, due to its importance in linear response theory. We further examine the validity of the recently proposed centroid path approximation recently proposed for reducing the computational cost of acquiring stopping power curves from RT-TDDFT simulations.

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“…The measured dissociation energy of the B + H and Al + H complexes are, however, rather different, 2.51 and 1.61 eV, respectively, indicating a different kind of bonding configuration in the two cases [8]. In contrast to n-type, hydrogen is easily incorporated into p-type SiC during CVD growth, but to a different degree in B-and Al-doped samples.…”

mentioning

confidence: 88%

“Some like it shallower” – p‐type doping in SiC

Deák

Aradi

Gali

et al. 2002

Physica Status Solidi (b)

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PACS 71.55.Ht, 71.55.Mb The usual p-type dopants of SiC, B, and Al, do not produce really shallow levels. In fact, boron can give rise to a secondary very deep acceptor level as well. The picture is complicated by hydrogen which is readily incorporated during in-growth doping into p-type material and can passivate both dopants but to a different degree. First principle calculations are reported regarding the interaction of hydrogen with B and Al in SiC. The results explain why hydrogen is incorporated in much higher amounts into B-doped than into Al-doped samples, and also reveal the influences of hydrogen on boron to produce the shallower acceptor. It will be shown that hydrogen incorporation during growth does not influence Al. Finally an Al -N -Al complex is proposed as a shallower acceptor in SiC.Introduction Silicon carbide is a wide band gap semiconductor intended for use in high power, high temperature electronics. This fact increases somewhat the tolerance for what can be termed a shallow level, still the traditional p-type dopants, boron and aluminium, seem to behave rather unsatisfactorily in SiC. Boron can produce a deep acceptor state about 0.55 eV above the valence band, as well as a shallower one at 0.30 eV [1], and it is not clear why the former appears. Aluminium gives only one level at about 0.21 eV [2], which is still too high for planned high-frequency devices operating at moderate temperatures. (Note that SiC comes in many different polytypes, the most important ones being the cubic 3C and the hexagonal 4H and 6H. The numbers here denote the number of inequivalent Si-C bilayers stacked on each other within one period along the cubic [111] or the hexagonal [0001] direction. Unless otherwise noted, values quoted refer to the 4H polytype.) Doping of SiC is complicated by two facts. For one, in a compound semiconductor dopants can choose between the two sublattices where they can behave rather differently. Second, the strong bonds and tight structure of SiC precludes diffusion doping. Therefore, doping may be achieved in growth during chemical vapour deposition (CVD) of homoepitaxial layers, or by implantation. The former procedure introduces hydrogen impurities, the latter causes intrinsic point defects -in both cases the dopants may form complexes.As for the site selection, the behaviour of Al is relatively predictable: it prefers the silicon site (Al Si ), where it fits in more conveniently, and produces the "shallow" acceptor level mentioned above. Boron, on the other hand, has been reported to occupy both, the silicon and the carbon site, alas, with preference for the Si site [3]. If SiC is grown under Si-rich conditions in CVD (offer of empty C sites for B), the boron incorporation is substantially lower than in the case of C-rich conditions (offer of empty Si sites). The latter (C-rich growth) produces the "shallow" acceptors mentioned above while the "deep" ones were observed in the former (Si-rich growth). Therefore, although no conclusive proof has yet been

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Hydrogen diffusion, complex formation, and dissociation in acceptor-doped silicon carbide

Cited by 57 publications

References 28 publications

Annealing behavior of the EB-centers and M-center in low-energy electron irradiated n-type 4H-SiC

Annealing behavior of the EB-centers and M-center in low-energy electron irradiated n-type 4H-SiC

Electronic stopping for protons andαparticles from first-principles electron dynamics: The case of silicon carbide

“Some like it shallower” – p‐type doping in SiC

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