Fabrication of Smooth Surface on 4H-SiC Substrate by Ultraviolet Assisted Local Polishing in Hydrogen Peroxide Solution

2012 ◽  
Vol 523-524 ◽  
pp. 24-28 ◽  
Author(s):  
Akihisa Kubota ◽  
Kazuya Kurihara ◽  
Mutsumi Touge

In this study, we investigated the possibility of removing and smoothing a single-crystal silicon carbide (SiC) surface under ultraviolet (UV) irradiation in hydrogen peroxide (H2O2) solution. In this method, a SiC substrate was excited by UV irradiation that transmitted synthetic quartz, and then an oxide layer on the SiC substrate was formed by photochemical reaction. Simultaneously, hydroxyl radical (OH*) was generated by the decomposition of H2O2 solution by UV irradiation. OH* plays an important role of oxidation of SiC surface. With these chemical reactions, oxide layer was effectively formed on the SiC surface. Finally, the oxide layer generated on a SiC substrate was chemically and/or mechanically removed by synthetic quartz and solutions. The polishing characteristics of this method were investigated by controlling the process parameters. Additionally, surface quality and removal depth were measured and evaluated by a phase-shift interference microscopy. Obtained results show that the surface morphology and the removal rate are strongly dependent on the existence of the UV irradiation. Moreover, it is shown that the removal characteristics of the SiC substrate depend on the process parameters such as the process time, reciprocating speed, and contact load. The processed surface has revealed that many scratches on the preprocessed surface was completely removed. The microroughness of the processed surface was improved to 0.15 nm (Rms) and 1.62 nm (p-v), respectively. These results provide useful information for obtaining an atomically smooth SiC surface.

2015 ◽  
Vol 656-657 ◽  
pp. 446-449
Author(s):  
Takahiro Takita ◽  
Hiroaki Ando ◽  
Akihisa Kubota ◽  
Mutsumi Touge

In this study, we investigated the possibility of smoothing a GaN substrate utilizing ultraviolet (UV) assisted polishing method in potassium hydroxide (KOH) solution. In this polishing method, GaN substrate was excited by an UV radiation, and then an oxide layer on the GaN substrate was formed by photochemical reaction. Simultaneously, generated oxide layer was removed by synthetic quartz tool and chemically etched by KOH solution. Finally, smoothed GaN surface could be realized. The surface quality and removal depth were measured and evaluated using a scanning white light interferometer and Normalski type differential interference microscopy. Obtained results show that the surface morphology and the removal rate are strongly dependent on the existence of the UV irradiation. Moreover, the processed surface has revealed that many scratches on the preprocessed GaN surface could be completely removed. The microroughness of the processed GaN surface profile was improved to be 0.18 nm (Rms), 1.06 nm (Rz).


2021 ◽  
Vol 11 (4) ◽  
pp. 1783
Author(s):  
Ming-Yi Tsai ◽  
Kun-Ying Li ◽  
Sun-Yu Ji

In this study, special ceramic grinding plates impregnated with diamond grit and other abrasives, as well as self-made lapping plates, were used to prepare the surface of single-crystal silicon carbide (SiC) wafers. This novel approach enhanced the process and reduced the final chemical mechanical planarization (CMP) polishing time. Two different grinding plates with pads impregnated with mixed abrasives were prepared: one with self-modified diamond + SiC and a ceramic binder and one with self-modified diamond + SiO2 + Al2O3 + SiC and a ceramic binder. The surface properties and removal rate of the SiC substrate were investigated and a comparison with the traditional method was conducted. The experimental results showed that the material removal rate (MRR) was higher for the SiC substrate with the mixed abrasive lapping plate than for the traditional method. The grinding wear rate could be reduced by 31.6%. The surface roughness of the samples polished using the diamond-impregnated lapping plate was markedly better than that of the samples polished using the copper plate. However, while the surface finish was better and the grinding efficiency was high, the wear rate of the mixed abrasive-impregnated polishing plates was high. This was a clear indication that this novel method was effective and could be used for SiC grinding and lapping.


1983 ◽  
Vol 27 ◽  
Author(s):  
S.S. Gill ◽  
I. H. Wilson

ABSTRACTSingle crystal silicon was implanted with 80, 120, 160 and 240 keV oxygen ions. Rutherford backscattering (RBS) analysis was used to obtain the implanted oxygen profile and the oxygen to silicon ratio in the implanted layer for doses in the range 1016 to 1.5 × 1018 O2+ cm−2 for room temperature implants. The depth and the thickness of the buried oxide layer has been measured as a function of implantation energy and oxygen dose. Chemical formation of stoichiometric SiO2 was confirmed by infra-red (IR) spectroscopy. Both RBS and IR indicate that once a surface oxide layer is formed for very high dose levels, the layer thickness decreases with increasing implanted dose beyond a critical dose level.


2016 ◽  
Vol 163 ◽  
pp. 523-532 ◽  
Author(s):  
Toshiyuki Tsuchiya ◽  
Kenji Miyamoto ◽  
Koji Sugano ◽  
Osamu Tabata

2002 ◽  
Vol 734 ◽  
Author(s):  
R. Govinthasamy ◽  
J. H. Rhee ◽  
S. C Sharma

ABSTRACTHighly conducting thin films of C60 were deposited by thermal evaporation in high vacuum on single crystal silicon substrates. The microstructure of the films was characterized by using Atomic Force Microscopy, and laser Raman spectroscopy. The films were polymerized by uv irradiation. The dc electrical resistivities of the as-deposited and uv-polymerized films were measured as functions of temperature between 295 and 17K by the four-probe technique. We present results on the effects of uv-irradiation on the surface microstructure and the temperature dependence of the electrical resistivity of these films.


1986 ◽  
Vol 68 ◽  
Author(s):  
Patrice Geraghty ◽  
W. Lee Smith

AbstractA method is presented to nondestructively monitor damage in silicon caused by reactive-ion or plasma etching on actual product wafers or test wafers immediately following the etch step.Data is taken on product wafers by scanning the 1-micron laser probe spot across and along the bottom of RIE-etched trenches.The onset of silicon damage brings a marked increase to the thermal wave (TW) signal: as the RIE bias voltage was increased from -60 volts to -250 volts, the TW signal increased monotonically by 1230%.The effects of other RIE process parameters on the damage level were also measured.This study allowed the RIE process variables to be adjusted to minimize damage to the silicon surface.


2017 ◽  
Vol 739 ◽  
pp. 157-163
Author(s):  
Guan Fu Lin ◽  
Ming Yi Tsai ◽  
Chiu Yuan Chen

This paper presents a combined diamond-impregnated lapping plate for single crystal silicon carbide (SiC) to improve the material removal rate due to SiC having very low material removal rate. Three different dimaond shapes were prepared: (1) "sharp," a sharp-edged diamod; (2) "blocky," a high quality crystalline diamond; (3) "oxidized diamond". The diamonds were manufactured by using high temperature heating method in a furnace to induce diamond oxidation resulting in improvement of Ra and sharpness of the diamonds. Three combined diamond-impregnated lapping plates were fabricated using the above mentioned diamond shapes with diamond size of 6μm. The surface roughness and removal rate of the SiC lapping with these plate were investigated. Experimental results showed that the average material removal rate (MRR) of oxidized diamond is higher than that of the other diamond shapes. The MRR of oxidized diamond for C-face and Si-face SiC are 4.72μm/hr and 6.26μm/hr, respectively. It is found that the surface roughness (Ra) of oxidized diamond for C-face and Si-face are 7.547nm and 8.06nm, respectively. This indicates that the combined diamond-impregnated lapping plate can be effectively used for SiC machining.


2001 ◽  
Vol 671 ◽  
Author(s):  
Chunhong Zhou ◽  
Lei Shan ◽  
S.H. Ng ◽  
Robert Hight ◽  
Andrew. J. Paszkowski ◽  
...  

ABSTRACTThis paper reports on the effect of colloidal abrasive particle size in the polishing of thermally grown silicon dioxide on 100mm diameter, P-type, (100), single crystal silicon wafers. The abrasive particle sizes were varied in six (6) slurries with pH values of 10.97 ± 0.08. The abrasive sizes were 10, 20, 50, 80, 110 and 140nm in diameter, and the slurry contained 30 weight percent abrasives. The experimental results indicate that the material removal rate (MRR) varies with the volume of the particle size. Results also confirm that there exists an optimum abrasive particle size with respect to material removal rate and surface finish. For a pad surface roughness of 5.2μm (Ra), the slurry containing 80nm particles resulted in the highest material removal rate and best surface finish. A nano-film model based on the pad roughness is used to explain the results.


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