Single event gate rupture in SiC MOS capacitors with different gate oxide thicknesses

Deki, Manato*; Makino, Takahiro; Kojima, Kazutoshi*; Tomita, Takuro*; Oshima, Takeshi

Materials Science Forum, 778-780, p.440 - 443, 2014/02

https://doi.org/10.4028/www.scientific.net/MSF.778-780.440

no abstracts in English

Breakdown voltage in silicon carbide metal-oxide-semiconductor devices induced by ion beams

Oshima, Takeshi; Deki, Manato; Makino, Takahiro; Iwamoto, Naoya; Onoda, Shinobu; Hirao, Toshio*; Kojima, Kazutoshi*; Tomita, Takuro*; Matsuo, Shigeki*; Hashimoto, Shuichi*

AIP Conference Proceedings 1525, p.654 - 658, 2013/04

https://doi.org/10.1063/1.4802408

Metal-Oxide-Semiconductor (MOS) capacitors were fabricated on n-type 4H-SiC epitaxial layers, and the leakage current through the gate oxide during heavy ion irradiation was investigated in order to evaluate dielectric breakdown induced by heavy ions (Single Event Gate Rupture: SEGR). The gate oxide at thickness ranges between 60 and 80 nm was formed using pyrogenic oxidation at 1100 C for 60 min. Circular electrodes with 180 diameter were formed using Al evaporation and a lift-off technique. The leakage current observed through the gate oxide was monitored during 18 MeV oxygen (O) or nickel (Ni) ions. As a result, although no significant difference in the value of the electric field at the dielectric breakdown (around 8.2 MV/cm) was observed between non-irradiated and 18 MeV-O irradiated samples, the value decreased to be 7.3 MV/cm in the case of 18 MeV-Ni ion incidence. The Linier Energy Transfer (LET) for 18 MeV-O is 7 MeV cm/mg, and this value is smaller than that for 18 MeV-Ni (24 MeV cm/mg). Also, 18 MeV-Ni ions deposit energy in narrower regions than 18 MeV-O ions. Thus, it can be concluded that the high density of charge induced by 18 MeV-Ni ions triggers SEGR in SiC MOS capacitors.

Heavy-ion-induced charge enhancement in 4H-SiC schottky barrier diodes

Makino, Takahiro; Deki, Manato; Iwamoto, Naoya; Onoda, Shinobu; Hoshino, Norihiro*; Tsuchida, Hidekazu*; Oshima, Takeshi

Proceedings of 10th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-10) (Internet), p.66 - 69, 2012/12

Silicon carbide (SiC) is regarded as a promising candidate for electronic devices requiring high radiation tolerance (rad-hard devices). Some results indicate that SiC has superior radiation tolerance from the point of view of total ionizing dose effects (TIDs). For the development of rad-hard SiC devices, it is necessary to understand the response of their performance when dense charge is generated in them by an incident ion, resulting in single event effects (SEEs). Therefore, we have measured the bias dependence of the collected charge distribution induced by heavy ions in 4H-SiC-schottky barrier diodes (SBDs) fabricated in thick epi-layer to reveal SEE mechanisms. As a result, anomalous collected charge peaks (2nd peaks) induced by the heavy ions were observed for the first time. The new process of the SEB was observed in the case of incident ions on thick epi-layer of SiC-SBDs.

Refreshable decrease in peak height of ion beam induced transient current from silicon carbide metal-oxide-semiconductor capacitors

Oshima, Takeshi; Iwamoto, Naoya; Onoda, Shinobu; Makino, Takahiro; Deki, Manato; Nozaki, Shinji*

AIP Conference Proceedings 1336, p.660 - 664, 2011/05

https://doi.org/10.1063/1.3586184

Metal-Oxide-Semiconductor (MOS) capacitors were fabricated on n-type 4H- and 6H-SiC epitaxial layers, and transient currents induced in SiC MOS capacitors by ion incidence were investigated. Transient Ion Beam Induced Current (TIBIC) measurements were performed using 15 MeV oxygen ions. As a result, the TIBIC peak height decreased with increasing number of incident ions. For example, the TIBIC signal peak for a 4H-SiC MOS capacitor at a reverse bias of 15 V was 0.18 mA at the beginning. The peak decreased to be 0.10 mA after 1800 ion irradiation. After that, the forward bias of 1 V was applied to the MOS capacitor and the TIBIC measurements were carried out under the same conditions. As a result, the peak height was recovered to be 0.18 mA. In general, the response of charge de-trapping by deep levels in wide bandgap semiconductors is very slow and they act as fixed charge. Since dense electron-hole pairs are generated by ion incident and holes move to the SiO/SiC interface by the electric field (applied reverse bias). Therefore, the decrease in TIBIC signal peak can be interpreted in terms of the recombination of negatively charged acceptor type deep levels with ion induced holes.

Laser modification aiming at the enhancement of local electrical conductivities in SiC

Deki, Manato; Ito, Takuto*; Tomita, Takuro*; Matsuo, Shigeki*; Hashimoto, Shuichi*; Kitada, Takahiro*; Isu, Toshiro*; Onoda, Shinobu; Oshima, Takeshi

Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.218 - 221, 2010/10

Single-shot picosecond interferometry with one-nanometer resolution for dynamical surface morphology using a soft X-ray laser

Suemoto, Toru; Terakawa, Kota*; Ochi, Yoshihiro; Tomita, Takuro*; Yamamoto, Minoru; Hasegawa, Noboru; Deki, Manato*; Minami, Yasuo*; Kawachi, Tetsuya

Optics Express (Internet), 18(13), p.14114 - 14122, 2010/06

https://doi.org/10.1364/OE.18.014114

Using highly coherent radiation at a wavelength of 13.9 nm from a Ag-plasma soft X-ray laser, we constructed a pump-and-probe interferometer based on a double Lloyd's mirror system. The spatial resolutions are evaluated with a test pattern, showing 1.8 micrometers lateral resolution, and 1-nm depth sensitivity. This instrument enables a single-shot observation of the surface morphology with a 7-ps time-resolution. We succeeded in observing a nanometer scale surface dilation of Pt films at the early stage of the ablation process initiated by a 70 fs near infrared pump pulse.

Observation of nano-scale fluctuation on solid surface by soft X-ray laser interferometer with highly temporal resolution

Ochi, Yoshihiro; Terakawa, Kota*; Suemoto, Toru*; Kawachi, Tetsuya; Hasegawa, Noboru; Tomita, Takuro*; Yamamoto, Minoru*; Deki, Manato*; Oba, Toshiyuki; Kaihori, Takeshi

no journal, , 

We developed a soft X-ray laser interferometer dedicated to the solid state physics. The interferometer enabled us to observe dynamical changes on the solid surface such as the photo-induced phase transition with picoseconds temporal resolution and nanometer special resolution (in z-axis). We carried out a performance test using static test pattern and confirmed the performance.

Development of high-rep soft-X-ray laser and its application on solid state physics

Ochi, Yoshihiro; Kawachi, Tetsuya; Hasegawa, Noboru; Terakawa, Kota*; Suemoto, Toru; Tomita, Takuro*; Yamamoto, Minoru*; Deki, Manato*; Tanaka, Momoko; Nishikino, Masaharu; et al.

no journal, , 

no abstracts in English

Development of high-repetition soft-X-ray laser and its application in solid state physics

Ochi, Yoshihiro; Kawachi, Tetsuya; Hasegawa, Noboru; Nishikino, Masaharu; Tanaka, Momoko; Oba, Toshiyuki; Kishimoto, Maki; Ishino, Masahiko; Imazono, Takashi; Kaihori, Takeshi; et al.

no journal, , 

no abstracts in English

Applications of laser driven plasma soft X-ray laser in JAEA

Ochi, Yoshihiro; Kawachi, Tetsuya; Terakawa, Kota*; Suemoto, Toru*; Yamamoto, Minoru*; Tomita, Takuro*; Deki, Manato*; Hasegawa, Noboru

no journal, ,