Step-Bunching Dependence of the Lifetime of MOS Capacitor on 4o Off-Axis Si-Face 4H-SiC Epitaxial Wafers

2014 ◽  
Vol 778-780 ◽  
pp. 611-614 ◽  
Author(s):  
Akira Bandoh ◽  
Kenji Suzuki ◽  
Yoshihiko Miyasaka ◽  
Hiroshi Osawa ◽  
Takayuki Sato
Keyword(s):  
Epitaxial Growth ◽  
Dielectric Breakdown ◽  
Metal Oxide Semiconductor ◽  
Time Dependent ◽  
Oxide Semiconductor ◽  
Mos Capacitor ◽  
Step Bunching ◽  
Time Dependent Dielectric Breakdown ◽  
Substrate Properties ◽  
Reduced Time

The step-bunching dependence of the lifetime of metal–oxide–semiconductor capacitors on 4° off-axis 4H-SiC epitaxial wafers was investigated. The effects of the C/Si ratios in epitaxial growth and the substrate properties were examined. Step-bunching was observed at the base of triangle or trapezoid defects. Step-bunching decreased as the C/Si ratio was reduced. Time-dependent dielectric breakdown (TDDB) measurements showed that the locations of short lifetime breakdowns closely matched step-bunching positions. TDDB measurements of four different commercial substrates showed clear differences in capacitor lifetime.

Direct Observation of Dielectric Breakdown at Step-Bunching on 4H-SiC

2015 ◽  
Vol 821-823 ◽  
pp. 468-471 ◽  
Author(s):  
Yuki Mori ◽  
Mieko Matsumura ◽  
Hirotaka Hamamura ◽  
Toshiyuki Mine ◽  
Akio Shima ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Surface Morphology ◽  
Dielectric Breakdown ◽  
Optical Emission ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Tem Analysis ◽  
Mos Capacitor ◽  
Step Bunching ◽  
Electrical Stress

The mechanism of dielectric breakdown of oxide on step-bunching of 4H-silicon carbide (SiC) was investigated. Comparing the surface morphology obtained before forming metal-oxide-semiconductor (MOS) capacitor and optical emission on the capacitor under electrical stress, it was cleared that current concentrates on step-bunching and it often caused preferential dielectric breakdown. Based on TEM analysis and the observation of time dependence of emission under the stress, a new model was proposed to explain the dielectric breakdown on step-bunching.

Reliability of 4H-SiC(000-1) MOS Gate Oxide Using N2O Nitridation

2009 ◽  
Vol 615-617 ◽  
pp. 557-560 ◽  
Author(s):  
Takuma Suzuki ◽  
Junji Senzaki ◽  
Tetsuo Hatakeyama ◽  
Kenji Fukuda ◽  
Takashi Shinohe ◽  
...  
Keyword(s):  
Dielectric Breakdown ◽  
Gate Oxide ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Band Offset ◽  
Mos Capacitors ◽  
Conduction Band Offset ◽  
Time Dependent Dielectric Breakdown ◽  
Oxide Reliability ◽  
Mos Gate

The oxide reliability of metal-oxide-semiconductor (MOS) capacitors on 4H-SiC(000-1) carbon face was investigated. The gate oxide was fabricated by using N2O nitridation. The effective conduction band offset (Ec) of MOS structure fabricated by N2O nitridation was increased to 2.2 eV compared with Ec = 1.7 eV for pyrogenic oxidation sample of. Furthermore, significant improvements in the oxide reliability were observed by time-dependent dielectric breakdown (TDDB) measurement. It is suggested that the N2O nitridation as a method of gate oxide fabrication satisfies oxide reliability on 4H-SiC(000-1) carbon face MOSFETs.

1.4kV Double-Implanted MOSFETs Fabricated on 4H-SiC(000-1)

2011 ◽  
Vol 679-680 ◽  
pp. 607-612 ◽  
Author(s):  
Hiroshi Kono ◽  
Takuma Suzuki ◽  
Kazuto Takao ◽  
Masaru Furukawa ◽  
Makoto Mizukami ◽  
...  
Keyword(s):  
Room Temperature ◽  
Dielectric Breakdown ◽  
Field Effect Transistors ◽  
Oxide Semiconductor ◽  
Gate Bias ◽  
Drain Voltage ◽  
Mos Capacitor ◽  
Time Dependent Dielectric Breakdown ◽  
Blocking Voltage ◽  
Switching Characteristics

1.2 mm × 1.2 mm and 2.7 mm × 2.7 mm silicon carbide double-implanted metal-oxide-semiconductor field-effect transistors (DIMOSFETs) were fabricated on 4H-SiC (000-1) carbon face. 1.2 mm × 1.2 mm DIMOSFETs were characterized from room temperature to 150°C. At room temperature, the specific on-resistance of this MOSFET was 5.7 mΩcm2 at a gate bias of 20 V and a drain voltage of 1.0 V. The blocking voltage of this MOSFET was 1450 V based on the avalanche current. At 150 °C, the specific on-resistance increased from 5.7 mΩcm2 to 9.1 mΩcm2 and the threshold voltage decreased from 4.9 V to 4.1 V. The blocking voltage increased from 1450V to 1500V. 2.7 mm × 2.7 mm DIMOSFETs were also characterized at room temperature. They showed a specific on-resistance of 8.0 mΩcm2 at a gate bias of 20 V and a drain voltage of 1 V. The blocking voltage of this device was 1550 V, which was determined by the avalanche current. The time-zero dielectric breakdown (TZDB) and time-dependent dielectric breakdown (TDDB) characteristics of 180 μm × 180 μm MOS capacitor were estimated. At room temperature (RT), TZDB was 9.3 MV/cm and the charge to breakdown value of 63% cumulative failure (Qbd) was 72 C/cm2. The temperature dependence of Qbd measurements showed that it deceased from 72 C/cm2 at RT to 14 C/cm2 at 250 °C. Switching characteristics of 1.2 mm × 1.2 mm DIMOSFETs were obtained by the double-pulse measurements. The turn-on time and the turn-off time were 36 nsec and 53 nsec, respectively.

Effect of Gate Wet Reoxidation on Reliability and Channel Mobility of Metal-Oxide-Semiconductor Field-Effect Transistors Fabricated on 4H-SiC(000-1)

2008 ◽  
Vol 600-603 ◽  
pp. 791-794 ◽  
Author(s):  
Takuma Suzuki ◽  
Junji Senzaki ◽  
Tetsuo Hatakeyama ◽  
Kenji Fukuda ◽  
Takashi Shinohe ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Field Effect ◽  
Dielectric Breakdown ◽  
Field Effect Transistors ◽  
Gate Oxide ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Channel Mobility ◽  
Time Dependent Dielectric Breakdown ◽  
Oxide Reliability

The channel mobility and oxide reliability of metal-oxide-semiconductor field-effect transistors (MOSFETs) on 4H-SiC (0001) carbon face were investigated. The gate oxide was fabricated by using dry-oxidized film followed by pyrogenic reoxidation annealing (ROA). Significant improvements in the oxide reliability were observed by time-dependent dielectric breakdown (TDDB) measurement. Furthermore, the field-effect inversion channel mobility (μFE) of MOSFETs fabricated by using pyrogenic ROA was as high as that of conventional 4H-SiC (0001) MOSFETs having the pyrogenic-oxidized gate oxide. It is suggested that the pyrogenic ROA of dry oxide as a method of gate oxide fabrication satisfies both channel mobility and oxide reliability on 4H-SiC (0001) carbon-face MOSFETs.

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