scholarly journals Study on precision dicing process of SiC wafer with diamond dicing blades

2021 ◽  
Vol 4 (3) ◽  
pp. 033004
Author(s):  
Xue Wang ◽  
Zewei Yuan ◽  
Peng Zhuang ◽  
Tianzheng Wu ◽  
Shuang Feng
Keyword(s):  
Sic Wafer

Low-Temperature Post-Oxidation Annealing Using Atomic Hydrogen Radicals Generated by High-Temperature Catalyzer for Improvement in Reliability of Thermal Oxides on 4H-SiC

2006 ◽  
Vol 527-529 ◽  
pp. 999-1002
Author(s):  
Junji Senzaki ◽  
Atsushi Shimozato ◽  
Kenji Fukuda
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Atomic Hydrogen ◽  
High Reliability ◽  
Hydrogen Atmosphere ◽  
Exposed Sample ◽  
New Apparatus ◽  
Hydrogen Radical ◽  
Hydrogen Radicals ◽  
Sic Wafer

Low-temperature post-oxidation annealing (POA) process of high-reliability thermal oxides grown on 4H-SiC using new apparatus that generates atomic hydrogen radicals by high-temperature catalyzer has been investigated. Atomic hydrogen radicals were generated by thermal decomposition of H2 gas at the catalyzer surface heated at high temperature of 1800°C, and then exposed to the sample at 500°C in reactor pressure of 20 Pa. The mode and maximum values of field-to-breakdown are 11.0 and 11.2 MV/cm, respectively, for the atomic hydrogen radical exposed sample. In addition, the charge-to-breakdown at 63% cumulative failure of the thermal oxides for atomic hydrogen radical exposed sample was 0.51 C/cm2, which was higher than that annealed at 800°C in hydrogen atmosphere (0.39 C/cm2). Consequently, the atomic hydrogen radical exposure at 500°C has remarkably improved the reliability of thermal oxides on 4H-SiC wafer, and is the same effect with high-temperature hydrogen POA at 800°C.

Ultra-precision grinding of 4H-SiC wafer by PAV/PF composite sol-gel diamond wheel

2021 ◽  
Vol 13 (9) ◽  
pp. 168781402110449
Author(s):  
Kaiping Feng ◽  
Tianchen Zhao ◽  
Binghai Lyu ◽  
Zhaozhong Zhou
Keyword(s):  
Surface Roughness ◽  
Low Temperature ◽  
Polyvinyl Alcohol ◽  
Feed Rate ◽  
Hot Pressing ◽  
Phenolic Resin ◽  
Sol Gel ◽  
Diamond Wheel ◽  
Sic Wafer ◽  
Better Than

To eliminate the deep scratches on the 4H-SiC wafer surface in the grinding process, a PVA/PF composite sol-gel diamond wheel was proposed. Diamond and fillers are sheared and dispersed in the polyvinyl alcohol-phenolic resin composite sol glue, repeatedly frozen at a low temperature of −20°C to gel, then 180°C sintering to obtain the diamond wheel. Study shows that the molecular chain of polyvinyl alcohol-phenolic resin is physically cross-linked to form gel under low-temperature conditions. Tested by mechanical property testing machines, microhardness tester, and SEM. The results show that micromorphology is more uniform, the strength of the sol-gel diamond wheel is higher, the hardness uniformity is better than that of the hot pressing diamond wheel. Grinding experiments of 4H-SiC wafer were carried out with the prepared sol-gel diamond wheel. The influence of grinding speed, feed rate, and grinding depth on the surface roughness was investigated. The results showed that by using the sol-gel diamond wheel, the surface quality of 4H-SiC wafer with an average surface roughness Ra 6.42 nm was obtained under grinding wheel speed 7000 r/min, grinding feed rate 6 µm/min, and grinding depth 15 µm, the surface quality was better than that of using hot pressing diamond wheel.

scholarly journals Breakdown Degradation Associated With Elementary Screw Dislocations In 4H-SiC P+N Junction Rectifiers

1997 ◽  
Vol 483 ◽  
Author(s):  
P. G. Neudeck ◽  
W. Huang ◽  
M. Dudley
Keyword(s):  
Video Camera ◽  
Initial Study ◽  
Hollow Core ◽  
Power Devices ◽  
Screw Dislocations ◽  
Burgers Vector ◽  
X Ray ◽  
Current Voltage ◽  
The Impact ◽  
Sic Wafer

AbstractIt is well-known that SiC wafer quality deficiencies are delaying the realization of outstandingly superior 4H-SiC power electronics. While efforts to date have centered on eradicating micropipes (i.e., hollow core super-screw dislocations with Burgers vector > 2c), 4H-SiC wafers and epilayers also contain elementary screw dislocations (i.e., Burgers vector = Ic with no hollow core) in densities on the order of thousands per cm2, nearly 100-fold micropipe densities. This paper describes an initial study into the impact of elementary screw dislocations on the reverse-bias current-voltage (I-V) characteristics of 4H-SiC p+n diodes. First, Synchrotron White Beam X-ray Topography (SWBXT) was employed to map the exact locations of elementary screw dislocations within small-area 4H-SiC p+n mesa diodes. Then the high-field reverse leakage and breakdown properties of these diodes were subsequently characterized on a probing station outfitted with a dark box and video camera. Most devices without screw dislocations exhibited excellent characteristics, with no detectable leakage current prior to breakdown, a sharp breakdown I-V knee, and no visible concentration of breakdown current. In contrast devices that contained at least one elementary screw dislocation exhibited a 5% to 35% reduction in breakdown voltage, a softer breakdown I-V knee, and visible microplasmas in which highly localized breakdown current was concentrated. The locations of observed breakdown microplasmas corresponded exactly to the locations of elementary screw dislocations identified by SWBXT mapping. While not as detrimental to SiC device performance as micropipes, the undesirable breakdown characteristics of elementary screw dislocations could nevertheless adversely affect the performance and reliability of 4H-SiC power devices.

Effect of Process Parameters on Material Removal Rate in Chemical Mechanical Polishing of 6H-SiC(0001)

2008 ◽  
Vol 600-603 ◽  
pp. 831-834 ◽  
Author(s):  
Joon Ho An ◽  
Gi Sub Lee ◽  
Won Jae Lee ◽  
Byoung Chul Shin ◽  
Jung Doo Seo ◽  
...  
Keyword(s):  
Material Removal Rate ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Colloidal Silica ◽  
Removal Rate ◽  
Mechanical Polishing ◽  
Diamond Particles ◽  
Average Grain Size ◽  
Silica Slurry ◽  
Sic Wafer

2inch 6H-SiC (0001) wafers were sliced from the ingot grown by a conventional physical vapor transport (PVT) method using an abrasive multi-wire saw. While sliced SiC wafers lapped by a slurry with 1~9㎛ diamond particles had a mean height (Ra) value of 40nm, wafers after the final mechanical polishing using the slurry of 0.1㎛ diamond particles exhibited Ra of 4Å. In this study, we focused on investigation into the effect of the slurry type of chemical mechanical polishing (CMP) on the material removal rate of SiC materials and the change in surface roughness by adding abrasives and oxidizer to conventional KOH-based colloidal silica slurry. The nano-sized diamond slurry (average grain size of 25nm) added in KOH-based colloidal silica slurry resulted in a material removal rate (MRR) of 0.07mg/hr and the Ra of 1.811Å. The addition of oxidizer (NaOCl) in the nano-size diamond and KOH based colloidal silica slurry was proven to improve the CMP characteristics for SiC wafer, having a MRR of 0.3mg/hr and Ra of 1.087Å.

SiC wafer bonding using surface activation method for power device

2017 ◽  
Author(s):  
Fengwen Mu ◽  
Masahisa Fujino ◽  
Tadatomo Suga ◽  
Kenichi Iguchi ◽  
Haruo Nakazawa ◽  
...  
Keyword(s):  
Wafer Bonding ◽  
Activation Method ◽  
Power Device ◽  
Surface Activation ◽  
Sic Wafer

Development of Multi-Wire Electric Discharge Machining for SiC Wafer Processing

2014 ◽  
Vol 778-780 ◽  
pp. 776-779 ◽  
Author(s):  
Masumi Ogawa ◽  
Kei Mine ◽  
Seiki Fuchiyama ◽  
Yasuhiro Tawa ◽  
Tomohisa Kato
Keyword(s):  
Electric Discharge ◽  
Wire Edm ◽  
Electric Discharge Machining ◽  
Entire Surface ◽  
Effective Removal ◽  
Diameter Ingot ◽  
Wire Electric Discharge Machining ◽  
Wafer Processing ◽  
Sic Wafer ◽  
Electric Discharge Pulse

In order to slice the larger size ingot toward 6 inch of silicon carbide (SiC), we are developing Multi-wire Electric Discharge Machining (EDM). To prevent wire break during slicing, we have developed the electric discharge pulse control system. So far, with 10 multi-wires, we have succeeded in slicing of 4 inch SiC balk single crystal without wire break. High quality slicing surface (e.g. small value of around 10 μm of SORI for 3 inchi wafer) was also achieved. By polishing methode, EDM-sliced wafer was estimated to have the uniform thickness of damaged layer over the entire surface. We confirmed that the wafer sliced by EDM can be processed in the later process, by grinding the 3 inch wafer. And it was confirmed that 6 inch ingot can be sliced with 10 multi-wire EDM, by slicing the boule of SiC poly crystal. For the larger diameter ingot than 4 inch, Multi-wire EDM will be practically used by the effective removal of machining chips from the machining clearance between the wire and work.

scholarly journals Marrying Medicine and Materials: Artemisinin (Qinghaosu) Particle is Soft Enough for Scratching Hard SiC Wafer in Water

2016 ◽  
Author(s):  
Yu-rong Zhu ◽  
Dan Zhang ◽  
Yang Gan ◽  
Fei-hu Zhang
Keyword(s):  
Pure Water ◽  
High Hardness ◽  
Underlying Mechanism ◽  
Molecular Solids ◽  
High Brightness ◽  
Force Microscopy ◽  
Atomic Force ◽  
Chemical Inertness ◽  
Sic Wafer ◽  
First Time

<p>Silicon carbide (SiC) single crystals, along with sapphire and silicon, are one of most important substrates for high-brightness LED fabrications. Owing to extremely high hardness (Mohs&rsquo; scale of 9.5) and chemical inertness, the polishing rate of SiC with conventional chemical mechanical polishing (CMP) methods is not high, and surface scratches are also inevitable because of using slurry containing hard abrasives such as silica particles. Here artemisinin (Qinghaosu) crystals, very soft molecular solids, were found, for the first time to the best of our knowledge, to effectively polish SiC wafers even in pure water as demonstrated by proof-of-concept scratching experiments using atomic force microscopy (AFM). The underlying mechanism is attributed to activated oxidation of SiC by mechanically released reactive &middot;OH free radicals from the endoperoxide bridges. The preliminary results reported here have important implications for developing novel alternative green and scratch-free polishing methods for hard-brittle substrates including SiC and others.</p>

Surface Polishing of 2-Inch 4H-SiC Wafer Using Fe Abrasive Particles

2012 ◽  
Vol 516 ◽  
pp. 487-491 ◽  
Author(s):  
Akihisa Kubota ◽  
Yuya Ichimori ◽  
Mutsumi Touge
Keyword(s):  
Differential Interference Contrast Microscopy ◽  
Abrasive Particles ◽  
Power Semiconductor ◽  
Force Microscopy ◽  
Surface Polishing ◽  
Atomic Force ◽  
Chemical Inertness ◽  
Nomarski Differential Interference Contrast ◽  
Interference Contrast Microscopy ◽  
Sic Wafer

Ultra smooth and defect-free 4H-SiC wafers are strongly demanded in the next-generation power semiconductor devices. However, such SiC substrates are relatively difficult to machine because of their mechanical hardness and marked chemical inertness. In this study, we attempt to polish 2-inch 4H-SiC wafers by our proposed method, which utilizes Fe particles and a hydrogen peroxide solution. The processed surface was observed by phase shift interferometric microscopy, Nomarski differential interference contrast microscopy and atomic force microscopy. These observational results show that the surface roughness was improved over the entire 2-inch wafer by our proposed method. These results offer useful information for preparing a smooth SiC wafer.

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