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Yan, F.*; Devaty, R. P.*; Choyke, W. J.*; Gali, A.*; Kimoto, Tsunenobu*; Oshima, Takeshi; Pensl, G.*
Applied Physics Letters, 100(13), p.132107_1 - 132107_3, 2012/03
Times Cited Count：4 Percentile：17.79(Physics, Applied)
- and He-implantation or by irradiation with high-energy electronsWeidner, M.*; Trapaidze, L.*; Pensl, G.*; Reshanov, S. A.*; Sch
ner, A.*; Ito, Hisayoshi; Oshima, Takeshi; Kimoto, Tsunenobu*
Materials Science Forum, 645-648, p.439 - 442, 2010/00
Intrinsic defects in 3C-SiC generated by implantation of H and He ions or by irradiation of high energy electrons were investigated using DLTS (Deep Level Transient Spectroscopy). The defect parameters and the thermal stability of the observed defects are determined. The dominant DLTS peak was named W6-center and its capture-cross-section was directly measured by variation of the filling pulse length. The charge state of the W6-center is obtained from double-correlated DLTS investigations according to the Poole-Frenkel effect.
-implnated Al-doped 4H-SiC epilayersBeljakowa, S.*; Reshanov, S. A.*; Zippelius, B.*; Krieger, M.*; Pensl, G.*; Danno, Katsunori*; Kimoto, Tsunenobu*; Onoda, Shinobu; Oshima, Takeshi; Yan, F.*; et al.
Materials Science Forum, 645-648, p.427 - 430, 2010/00
Defects in Al-doped p-type 4H-SiC were investigated using admittance spectroscopy (AS). Also, defects in 4H-SiC irradiated with electrons and He ions were studied using AS. As a result, a shallow level with activation energy at 170 meV was found and is has the capture cross section of 3.5
10
/cm
which is extremely low value. The concentration of the defect did not change even after electron and He irradiations. Also, the defect can be found after annealing at 1800 
C. Therefore, we can conclude that the defect is a very stable intrinsic defect in SiC.
He ion irradiated 4H SiCYan, F.*; Devaty, R. P.*; Choyke, W. J.*; Kimoto, Tsunenobu*; Oshima, Takeshi; Pensl, G.*; Gali, A.*
Materials Science Forum, 645-648, p.411 - 414, 2010/00
Silicon Carbide (SiC) samples were irradiated with electron, proton and He ions and defects in the irradiated SiC were investigated by Low Temperature Photo Luminescence (LTPL). After irradiation, PL spectra between 2.48 and 2.62 eV were measured at 7 K. As a results, several PL lines were observed. These lines showed the same annealing behavior and were annealed out between 1300 and 1400C. Therefore, it is concluded that these line have the same origin. In addition, as a result of simulation, the structure of the defect is determined to be di-carbon antisite.
Reshanov, S. A.*; Beljakowa, S.*; Zippelius, B.*; Pensl, G.*; Danno, Katsunori*; Alfieri, G.*; Kimoto, Tsunenobu*; Onoda, Shinobu; Oshima, Takeshi; Yan, F.*; et al.
Materials Science Forum, 645-648, p.423 - 426, 2010/00
n- and p-type 4H-SiC epilayers were irradiated with electrons at 170 keV or 1 MeV. Subsequent annealing (in Ar, 30 min) up to 1700 C was carried out. Defects in the samples were investigated using DLTS (Deep Level Transient Spectroscopy). As a results, for n-type, dominant defects were Z1/Z2 and EH7, and they can observed for both 170 keV- and 1 MeV-irradiated samples. Both defects decreased with increasing temperature up to 1100 C, although they appeared again at 1400 C. Then they disappeared at 1600 C. For p-type, defects named UK1 and HK2 were observed and they were very stable. No significant decrease was observed after 1700 C annealing.
Yan, F.*; Devaty, R. P.*; Choyke, W. J.*; Danno, Katsunori*; Alfieri, G.*; Kimoto, Tsunenobu*; Onoda, Shinobu; Oshima, Takeshi; Reshanov, S. A.*; Beljakowa, S.*; et al.
Materials Science Forum, 645-648, p.419 - 422, 2010/00
Defects in n- and p-type 4H-SiC epitaxial layer were investigated by low temperature photoluminescence spectroscopy (LTPL) and deep level transient spectroscopy (DLTS). Defects were introduced by either 170 keV or 1 MeV electron irradiation into samples at RT. The samples were annealed from 25C to 1700C in 100C steps. As a result of LTPL measurements, L
line was observed after irradiation. In previous studies, L line is thought to correlate with Z/Z
centers in DLTS measurements. However, in this study, no correlation between L and Z1/Z was observed.
-raysHishiki, Shigeomi; Reshanov, S. A.*; Oshima, Takeshi; Ito, Hisayoshi; Pensl, G.*
Materials Science Forum, 600-603, p.703 - 706, 2009/00
Times Cited Count：1 Percentile：46.72(Materials Science, Ceramics)N-channel 6H-SiC MOSFETs has been investigated radiation effect. The MOSFETs were irradiated by -rays up to 3.16 MGy(SiO) at room temperature. The electrical characteristic was estimated by Hall effect measurement and current vs. voltage measurement. The -rays irradiated MOSFETs were observed that channel mobility increased due to decrease interface traps.
Oshima, Takeshi; Hishiki, Shigeomi*; Iwamoto, Naoya; Reshanov, S. A.*; Pensl, G.*; Kojima, Kazutoshi*; Kawano, Katsuyasu*
Proceedings of the 26th Symposium on Materials Science and Engineering, Research Center of Ion Beam Technology Hosei University, p.31 - 34, 2007/12
no abstracts in English
Frank, T.*; Pensl, G.*; Tana-Zaera, R.*; Z
iga-P
rez, J.*; Mart
nez-Tom
s, C.*; Muoz-Sanjos, V.*; Oshima, Takeshi; Ito, Hisayoshi; Hofmann, D.*; Pfisterer, D.*; et al.
Applied Physics A, 88(1), p.141 - 145, 2007/07
Times Cited Count：48 Percentile：82.54(Materials Science, Multidisciplinary)Deep Level Transient Spectroscopy (DLTS) measurements were carried out to investigate defects in vapor-phase grown ZnO crystals. The generation of defect center labeled E4 subsequent to annealing in different ambients was monitored. By conducting electron irradiations with energies, where either both the Zn- and O-sublattice are damaged or according to only the Zn-lattice, a chemical assignment to the defect centers E4 and E3 could be accomplished. DLTS investigations of ZnO samples under illumination give an evidence that E4 is a negative-U center.
Lee, K. K.*; Laube, M.*; Oshima, Takeshi; Ito, Hisayoshi; Pensl, G.*
Materials Science Forum, 556-557, p.791 - 794, 2007/00
no abstracts in English
Pensl, G.*; Schmid, F.*; Reshanov, S.*; Weber, H. B.*; Bockstedte, M.*; Mattausch, A.*; Pankratov, O.*; Oshima, Takeshi; Ito, Hisayoshi
Materials Science Forum, 556-557, p.307 - 312, 2007/00
no abstracts in English
Schmid, F.*; Reshanov, S. A.*; Weber, H. B.*; Pensl, G.*; Bockstedte, M.*; Mattausch, A.*; Pankratov, O.*; Oshima, Takeshi; Ito, Hisayoshi
Physical Review B, 74(24), p.245212_1 - 245212_11, 2006/12
Times Cited Count：11 Percentile：46.43(Materials Science, Multidisciplinary)Hexagonal SiC is co-implanted with silicon Si, carbon C, or neon Ne ions along with nitrogen N ions. Also hexagonal SiC irradiated with electrons e
of 200 keV energy. During the subsequent annealing step at temperatures above 1450 C a deactivation of N donors and a reduction of the compensation are observed in the case of the Si/N co-implantation and e irradiation. Using Hall measurement, the N donor deactivation is studied as a function of the concentration of the co-implanted species and the annealing temperature. The formation of energetically deep defects is analyzed with deep level transient spectroscopy. A detailed theoretical analysis based on the density functional theory is conducted; it takes into account the kinetic mechanisms for the formation of N interstitial clusters and N-vacancy complexes. In accordance with all the experimental results, this analysis distinctly indicates that the (N
)
-V
complex, which is thermally stable at high temperatures, is responsible for the N donor deactivation.
-irradiated p-channel SiC metal-oxide-semiconductor field-effect transistors containing step bunchingLee, K. K.*; Oshima, Takeshi; Oi, Akihiko*; Ito, Hisayoshi; Pensl, G.*
Japanese Journal of Applied Physics, Part 1, 45(9A), p.6830 - 6836, 2006/09
Times Cited Count：17 Percentile：52.69(Physics, Applied)no abstracts in English
Pensl, G.*; Ciobanu, F.*; Frank, T.*; Kirmse, D.*; Krieger, M.*; Reshanov, S.*; Schmid, F.*; Weidner, M.*; Oshima, Takeshi; Ito, Hisayoshi; et al.
Microelectronic Engineering, 83(1), p.146 - 149, 2006/01
Times Cited Count：16 Percentile：60.55(Engineering, Electrical & Electronic)no abstracts in English
Laube, M.*; Pensl, G.*; Lee, K. K.; Oshima, Takeshi
Materials Science Forum, 457-460, p.1381 - 1384, 2004/10
The electrical properties of n-channel 6H-SiC MOSFETs have been studied by temperature-dependent current-voltage and Hall effect measurements. The MOS transistors are either wet (sample A) or dry oxidized followed by a post-annealing step at 1100C and a pyrogenic reoxidation at 800C (sample B). Higher drain transconductance and saturation currents are observed in sample B. The Hall effect investigations show that this improvement in the performance of the MOS transistors (sample B) is caused by a lower degree of trapping of free electrons. The density of interface traps D
close to the conduction band edge has been determined from the shift of the threshold voltage V
as a function of the temperature and from the Hall effect results. D is about two times lower in sample B. The room temperature value of the electron Hall mobility is determined to be about 60 cm/Vs for both samples; it increases with decreasing temperature.
Weidner, M.*; Pensl, G.*; Nagasawa, Hiroyuki*; Schner, A.*; Oshima, Takeshi
Materials Science Forum, 457-460, p.485 - 488, 2004/10
no abstracts in English
Kawasuso, Atsuo; Weidener, M.*; Redmann, F.*; Frank, T.*; Sperr, P.*; Kgel, G.*; Yoshikawa, Masahito; Ito, Hisayoshi; Krause-Rehberg, R.*; Triftsh
user, W.*; et al.
Silicon Carbide, p.563 - 584, 2004/00
no abstracts in English
Kawasuso, Atsuo; Yoshikawa, Masahito; Maekawa, Masaki; Ito, Hisayoshi; Chiba, Toshinobu*; Redmann, F.*; Rehberg, R. K.*; Weidner, M.*; Frank, T.*; Pensl, G.*
Materials Science Forum, 433-436, p.477 - 480, 2003/08
no abstracts in English
Kawasuso, Atsuo; Weidner, M.*; Redmann, F.*; Frank, T.*; Krause-Rehberg, R.*; Pensl, G.*; Sperr, P.*; Triftshuser, W.*; Ito, Hisayoshi
Materials Science Forum, 389-393, p.489 - 492, 2002/05
no abstracts in English
levels in electron-irradiated 4H-SiC studied by positron annihilation and deep-level transient spectroscopyKawasuso, Atsuo; Redmann, F.*; Krause-Rehberg, R.*; Weidner, M.*; Frank, T.*; Pensl, G.*; Sperr, P.*; Triftshuser, W.*; Ito, Hisayoshi
Applied Physics Letters, 79(24), p.3950 - 3952, 2001/12
Times Cited Count：40 Percentile：79.83(Physics, Applied)no abstracts in English
