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.

Electrical conduction properties of SiC modified by femtosecond laser

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

Proceedings of 12th International Symposium on Laser Precision Microfabrication (LPM 2011) (Internet), 5 Pages, 2011/06

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

Pulse pitch dependence of electric conduction by fs-laser-modification on 6H-SiC substrates

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

no journal, , 

no abstracts in English

Fluence dependence of local electrical conductivities in SiC irradiated with femtosecond laser

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

no journal, , 

no abstracts in English

Polarization dependence of local electric conductivities in femtosecond laser modified SiC

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

no journal, , 

no abstracts in English

Irradiation polarization dependence of local electrical conductivity of SiC modified by femtosecond laser, 2

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

no journal, , 

no abstracts in English

Linear energy transfer dependence of single event gate rupture in SiC MOS capacitors

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

no journal, , 

Single Event Gate Rupture (SEGR) in SiC MOS capacitors fabricated on 4H-SiC was studied. In particular, we evaluate the linear energy transfer (LET) dependence of critical electric field (Ecr) at which SEGR occurs in SiC MOS capacitors. The MOS capacitors were irradiated with either oxygen (O) or nickel (Ni) ions at 18 MeV. The leakage current through the gate oxide of the MOS capacitors was monitored under applied biases up to 100 V. The LET of O and Ni ions at 18 MeV are 7.02 and 23.8 MeV cm/mg, respectively. For No significant difference in Ecr between 18 MeV-O irradiated and non-irradiated (LET=0) samples was observed. This result suggests that charge density generated in SiC by 18 MeV-O was not enough to induce SEGR. On the other hand, Ecr for samples irradiated with 18 MeV-Ni was lower than that for a sample irradiated with 18 MeV-O. We confirmed that Ecr decreased with increasing LET of incident ions, and the relationship is similar to that of silicon MOS capacitors.