Dose Rate Dependence of the Amorphization of Silicon Carbide

1998 ◽  
Vol 540 ◽  
Author(s):  
L.L. Snead ◽  
S.J. Zinkle ◽  
W.S. Eatherly ◽  
D.K. Hensley ◽  
N.L. Vaughn ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Dose Rate ◽  
Amorphous Material ◽  
Dark Field ◽  
Theory Model ◽  
Ion Flux ◽  
Rate Dependence ◽  
Rate Theory ◽  
Crystal Silicon ◽  
Critical Dose

AbstractSingle crystal silicon carbide (SiC) has been 2 MeV silicon ion irradiated in various irradiation temperature and ion flux ranges to measure the effect of these parameters on the critical dose for amorphization. The temperature and flux range for which amorphization was observed ranged from 80 to 400 K and 0.066 to 3 × 104 dpa/s, respectively. The critical dose, Dcrit was found by locating the depth of the boundary between partially crystalline and fully amorphous material using dark field TEM from samples prepared in cross section. This depth was compared to the damage profile as calculated using the TRIM-96 code. The temperature dependence of Dcrit is found to agree well with previously reported values, though new evidence suggests a defect species becoming mobile in the 250-300 K range. Also of significance is that Dcrit was dependent on flux at 340 K, ranging from 0.79 displacements per atom at the lowest ion flux to ∼0.6 dpa at the highest flux level. The dose rate dependence of Dcrit, is compared with a chemical rate theory model previously described by the authors. It is seen that the dose rate dependence is substantially weaker than theorized. An extrapolation of the measured dose rate dependence is also compared with recent data on fast neutron amorphized SiC.

Numerical Simulation of Irradiation-Induced Grain-Boundary Phosphorous Segregation in Reactor Pressure Vessel Steels Using Rate Theory Model With First-Principles Calculations

2009 ◽  
Author(s):  
Ken-ichi Ebihara ◽  
Masatake Yamaguchi ◽  
Yutaka Nishiyama ◽  
Kunio Onizawa ◽  
Hiroshi Matsuzawa
Keyword(s):  
Grain Boundary ◽  
Dose Rate ◽  
Pressure Vessel ◽  
First Principles ◽  
Theory Model ◽  
Irradiation Temperature ◽  
Reactor Pressure Vessel ◽  
Rate Theory ◽  
First Principles Calculations ◽  
Reactor Pressure

The experimental results on neutron-irradiated reactor pressure vessel (RPV) steels have revealed grain boundary segregation of phosphorous (P) due to neutron irradiation, which may lead to intergranular fracture. Because of the lack of experimental database, however, the dependence of the segregation on variables such as dose, dose-rate, and temperature is not clear. Here, we incorporate the parameters determined by first-principles calculations into the rate theory model which was developed for bcc lattice on the basis of the fcc lattice model proposed by Murphy and Perks [1], and apply it to the simulation of irradiation-induced P segregation in bcc iron. We evaluate the grain boundary P coverage and discuss its dependence on dose-rate and irradiation temperature by comparing our results with previously reported results and experimental data. As results, we find that dose-rate does not affect the grain boundary P coverage within the range of our simulation condition and that the dependence on irradiation temperature differs remarkably from the previous results.

scholarly journals Novel Abrasive-Impregnated Pads and Diamond Plates for the Grinding and Lapping of Single-Crystal Silicon Carbide Wafers

2021 ◽  
Vol 11 (4) ◽  
pp. 1783
Author(s):  
Ming-Yi Tsai ◽  
Kun-Ying Li ◽  
Sun-Yu Ji
Keyword(s):  
Silicon Carbide ◽  
Wear Rate ◽  
Single Crystal ◽  
Traditional Method ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Single Crystal Silicon ◽  
Crystal Silicon ◽  
Diamond Grit ◽  
Ceramic Binder

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.

Dose-rate dependence in the production of point defects in quartz

1993 ◽  
Vol 44 (1-2) ◽  
pp. IN11-277 ◽  
Author(s):  
L.E. Halliburton ◽  
A. Hofstaetter ◽  
A. Scharmann ◽  
M.P. Scripsick ◽  
G.J. Edwards
Keyword(s):  
Dose Rate ◽  
Point Defects ◽  
Rate Dependence

Silicon Carbide Die Attach Scheme for 500°C Operation

2000 ◽  
Vol 622 ◽  
Author(s):  
Liang-Yu Chen ◽  
Gary W. Hunter ◽  
Philip G. Neudeck
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Electrical Resistance ◽  
Room Temperature ◽  
Semiconductor Devices ◽  
Single Crystal Silicon ◽  
Film Material ◽  
Crystal Silicon ◽  
Pure Alumina ◽  
Die Attach

ABSTRACTSingle crystal silicon carbide (SiC) has such excellent physical, chemical, and electronic properties that SiC based semiconductor electronics can operate at temperatures in excess of 600°C well beyond the high temperature limit for Si based semiconductor devices. SiC semiconductor devices have been demonstrated to be operable at temperatures as high as 600°C, but only in a probe-station environment partially because suitable packaging technology for high temperature (500°C and beyond) devices is still in development. One of the core technologies necessary for high temperature electronic packaging is semiconductor die-attach with low and stable electrical resistance. This paper discusses a low resistance die-attach method and the results of testing carried out at both room temperature and 500°C in air. A 1 mm2 SiC Schottky diode die was attached to aluminum nitride (AlN) and 96% pure alumina ceramic substrates using precious metal based thick-film material. The attached test die using this scheme survived both electronically and mechanically performance and stability tests at 500°C in oxidizing environment of air for 550 hours. The upper limit of electrical resistance of the die-attach interface estimated by forward I-V curves of an attached diode before and during heat treatment indicated stable and low attach-resistance at both room-temperature and 500°C over the entire 550 hours test period. The future durability tests are also discussed.

Dose Rate Dependence of Ion-Induced-Damage in Si Evaluated by Spectroscopic Ellipsometry

2001 ◽  
Vol 78-79 ◽  
pp. 341-344 ◽  
Author(s):  
Y. Murakami ◽  
H. Yamauchi ◽  
Taizoh Sadoh ◽  
A. Kenjo ◽  
Masanobu Miyao
Keyword(s):  
Dose Rate ◽  
Spectroscopic Ellipsometry ◽  
Rate Dependence
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