Shallow Defects Observed in As-Grown and Electron-Irradiated or He+-Implanted Al-Doped 4H-SiC Epilayers

Beljakowa, Svetlana; Reshanov, Sergey A.; Zippelius, Bernd; Krieger, Michael; Pensl, Gerhard; Danno, Katsunori; Kimoto, Tsunenobu; Onoda, Shinobu; Ohshima, Takeshi; Yan, Fei; Devaty, Robert P.; Choyke, Wolfgang J.

doi:10.4028/www.scientific.net/MSF.645-648.427

Paper Titles

New Lines and Issues Associated with Deep Defect Spectra in Electron, Proton and ⁴He Ion Irradiated 4H SiC
p.411

LTPL Investigation of N-Ga and N-Al Donor-Acceptor Pair Spectra in 3C-SiC Layers Grown by VLS on 6H-SiC Substrates
p.415

Thermal Histories of Defect Centers as Measured by Low Temperature Photoluminescence in n- and p-Type 4H SiC Epilayers Generated by Irradiation with 170 keV or 1 MeV Electrons
p.419

Thermal Stability of Defect Centers in n- and p-Type 4H-SiC Epilayers Generated by Irradiation with High-Energy Electrons
p.423

Shallow Defects Observed in As-Grown and Electron-Irradiated or He⁺-Implanted Al-Doped 4H-SiC Epilayers
p.427

A Laterally Resolved DLTS Study of Intrinsic Defect Diffusion in 4H-SiC after Low Energy Focused Proton Beam Irradiation
p.431

Metastable Defects in Low-Energy Electron Irradiated n-Type 4H-SiC
p.435

Deep Defects in 3C-SiC Generated by H⁺- and He⁺-Implantation or by Irradiation with High-Energy Electrons
p.439

Optical Characterization of VLS+CVD Grown 3C-SiC Films by Non-Linear and Photoluminescence Techniques
p.443

HomeMaterials Science ForumSilicon Carbide and Related Materials 2009Shallow Defects Observed in As-Grown and...

Shallow Defects Observed in As-Grown and Electron-Irradiated or He⁺-Implanted Al-Doped 4H-SiC Epilayers

Abstract:

Aluminum-doped 4H-SiC samples were either irradiated with high-energy electrons (170 keV or 1 MeV) or implanted with a box-shaped He+-profile. Admittance spectroscopy (AS) and deep level transient spectroscopy (DLTS) were employed to search for defect centers. AS spectra of as-grown as well as of electron-irradiated (170 keV or 1 MeV) 4H-SiC epilayers reveal the Al acceptor (ΔE(Al) = 200 meV) and an unknown defect (ΔE(SB) = 177 meV), while AS spectra of the He+-implanted and annealed sample show in addition to the Al-acceptor two energetically deeper acceptor-like defect centers (ΔE(RE3) = 255 meV and ΔE(KR3) = 375 meV). The KR3-center is not directly formed by the He+-implantation, it requires an annealing process. The DLTS spectra of the He+-implanted and annealed sample resolve a double-peak structure of the KR3-defect (ΔE(KR3A) = 380 meV and ΔE(KR3B) = 410 meV).

Info:

Periodical:

Materials Science Forum (Volumes 645-648)

Main Theme:

Silicon Carbide and Related Materials 2009

Edited by:

Anton J. Bauer, Peter Friedrichs, Michael Krieger, Gerhard Pensl, Roland Rupp and Thomas Seyller

Pages:

427-430

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.645-648.427

Citation:

S. Beljakowa et al., "Shallow Defects Observed in As-Grown and Electron-Irradiated or He⁺-Implanted Al-Doped 4H-SiC Epilayers", Materials Science Forum, Vols. 645-648, pp. 427-430, 2010

Online since:

April 2010

Authors:

Svetlana Beljakowa, Sergey A. Reshanov, Bernd Zippelius, Michael Krieger, Gerhard Pensl, Katsunori Danno, Tsunenobu Kimoto, Shinobu Onoda, Takeshi Ohshima, Fei Yan, Robert P. Devaty, Wolfgang J. Choyke

Keywords:

Admittance Spectroscopy, Electron Irradiation, Shallow Defects

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References

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[2] S. A. Reshanov, O. Klettke, G. Pensl: Mater. Sci. Forum Vol. 433-436 (2003), p.279.

[3] K. Danno, T. Kimoto, H. Matsunami: Appl. Phys. Lett. Vol. 86 (2005), 122104.

[4] L. Storasta, I. Kamata, T. Nakamura, H. Tsuchida: Mater. Sci. Forum Vol. 527-529 (2006), p.489.

[5] K. Danno, T. Kimoto: J. Appl. Phys. Vol. 101 (2007), 103704.

[6] S. A. Reshanov, S. Beljakowa, B. Zippelius, G. Pensl et al.: in these Conference Proceedings.

Paper TitlePages

Reduction in Al Acceptor Density by Electron Irradiation in Al-Doped 4H-SiC

Authors: Hideharu Matsuura, K. Aso, S. Kagamihara, Hisaomi Iwata, T. Ishida, K. Nishikawa

751

Technological Aspects of Ion Implantation in SiC Device Processes

Authors: Yuki Negoro, Tsunenobu Kimoto, Hiroyuki Matsunami

Abstract: Technological aspects of ion implantation in SiC device processes are described. Annealing techniques to suppress surface roughening of implanted SiC (0001) are demonstrated. Trials to achieve a low sheet resistance are described for n-type and p-type doping. Implantation into the (11-20) face is also presented. Electrical behaviors of implants near implanted tail regions are discussed based on experiments.

599

Mechanisms of Decrease in Hole Concentration in Al-Doped 4H-SiC by Irradiation of 200 keV Electrons

Authors: Hideharu Matsuura, Nobumasa Minohara, Yusuke Inagawa, Miyuki Takahashi, Takeshi Ohshima, Hisayoshi Itoh

Abstract: From the temperature dependence of the hole concentration p(T) in a lightly Al-doped 4H-SiC epilayer irradiated with several fluences of 200 keV electrons, the density of Al acceptors with 0.2 V E + eV decreases significantly with increasing fluence, whereas the density of unknown defects with 0.37 V E + eV increases with fluence and then decreases slightly. Although only C vacancies increase with fluence because 200 keV electrons can displace only C atoms, only the increase in the density of C monovacancies cannot explain the changes of p(T) by 200 keV electron irradiation. It may be necessary to consider the relationship between C vacancies and Al acceptors.

379

Z_1/2- and EH₆-Center in 4H-SiC: Not Identical Defects ?

Authors: Bernd Zippelius, Alexander Glas, Heiko B. Weber, Gerhard Pensl, Tsunenobu Kimoto, Michael Krieger

Abstract: Deep Level Transient Spectroscopy (DLTS) and Double-correlated DLTS (DDLTS) measurements have been conducted on Schottky contacts fabricated on n-type 4H-SiC epilayers using different contact metals in order to separate the EH₆- and EH₇-centers, which usually appear as a broad double peak in DLTS spectra. The activation energy of EH₆ (E_C - E_T(EH₆) = 1.203 eV) turns out to be independent of the electric field. As a consequence, EH₆ is acceptor-like according to the missing Poole-Frenkel effect. Therefore, it can be excluded that the EH₆-center and the prominent acceptor-like Z_1/2-center belong to different charge states of the same microscopic defect as theoretically suggested. It is proposed that EH₆ is a complex containing a carbon vacancy and another component available at high concentrations. The activation energy of EH₇ (E_C - E_T(EH₇) = 1.58 eV) has been evaluated indirectly by fitting the DLTS spectra of the EH_6/7 double peak taking the previously determined parameters of EH₆ into account.

251

Deep Levels in P-Type 4H-SiC Induced by Low-Energy Electron Irradiation

Authors: Kazuki Yoshihara, Masashi Kato, Masaya Ichimura, Tomoaki Hatayama, Takeshi Ohshima

Abstract: We have characterized deep levels in as-grown and electron irradiated p-type 4H-SiC epitaxial layers by the current deep-level transient spectroscopy (I-DLTS) method. A part of the samples were irradiated with electrons in order to introduce defects. As a result, we found that electron irradiation to p-type 4H-SiC created complex defects including carbon vacancy or interstitial. Moreover, we found that observed deep levels are different between before and after annealing, and thus annealing may change structures of defects.

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