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In this paper the authors investigate the effect of implantation temperature on the structural properties of diamond implanted with high fluences of Si between 5.3×1017 Si cm-2 and 1×1018 Si cm-2. In order to reduce radiation-induced damage and to enhance SiC formation the implantations were performed at elevated temperatures in the range from 900 to 1200 °C. Subsequently, all samples were annealed for 10 min at 1500 °C in a rf-heated furnace. X-ray diffraction revealed the formation of cubic SiC nanocrystallites in a buried layer inside the implanted diamond. The implantation-induced damage was assessed by analyzing graphitization of the surface-near layer using Raman spectroscopy. With increasing Si fluence the implantation-induced damage rises and the nearly perfect alignment of the formed SiC crystallites within the host diamond lattice deteriorates. However, raising the implantation temperature from 900 to 1000 °C reduces the damage in the diamond and increases the amount, size, and epitaxial alignment of the crystalline SiC precipitates. Further increase of the implantation temperature gives no improvement in the quality of the SiC-rich layer. Instead, the damaged diamond converts into graphite and the formation of SiC crystallites is obstructed. [ABSTRACT FROM AUTHOR]

Al supersaturated SiC layers (5×1020 Al cm-3) were produced by multienergy, high-dose ion implantation into 6H- and 4H-SiC. Several implantation schemes with varying implantation sequence and temperature were investigated. In dependence on the implantation conditions damaged single-crystalline, amorphous, or nanocrystalline layers were formed. The layer morphology and Al distribution in the as-implanted state as well as structural changes and related Al redistribution after high-temperature annealing (1500–1700 °C) were characterized by cross-sectional transmission electron microscopy, Rutherford backscattering spectrometry in combination with ion channeling, atomic force microscopy, and secondary-ion mass spectrometry. Remarkable Al redistribution effects have been found after annealing of Al supersaturated SiC. During high-temperature annealing Al atoms in excess to the solid solubility (2×1020 Al cm-3) tend to precipitate in single-crystalline SiC whereas they diffuse out in amorphous or nanocrystalline SiC. Redistribution of Al with concentration below the solid solubility is governed by transient enhanced diffusion which can be controlled by the annealing scheme. Amorphization of SiC is advantageous in the case of Al doping to levels higher than the solid solubility because it prevents Al precipitation during annealing and helps to form boxlike Al profiles with smooth plateau and abrupt edge. [ABSTRACT FROM AUTHOR]

Presents information on a study which discussed the phase formation due to high dose of aluminum implantation into silicon carbide. Microstructure; Chemical reactions and compositional changes; Conclusions.

Studies the effects of high dose ion irradiation through amorphous surface layers on single crystalline of silicon carbide at elevated temperatures. How to interpret the interface shift under ion irradiation; Experimental details; Results and discussion; Conclusions.

Cites an experimental investigation into the ion fluence and temperature dependence of the amorphization of silicon carbide (SiC) using laser reflectometry and Rutherford backscattering spectometry. Information on SiC; Details on the amorphization models used in the investigation; In-depth look at the experiment; Results of the experiment.

Focuses on a study which examined amorphization of 6H-SiC with germanium ions at room temperature and subsequent ion-beam-induced epitaxial crystallization (IBIEC) with silicon ions. Significance of SiC to the semiconductor industry; Experimental results; Results and discussion.

Presents information on a study that performed the analysis of silicon carbide films obtained by carbon ion implantation into amorphous by infrared and Raman scattering spectroscopies, transmission electron microscopy. Experimental procedure; Results and discussion on the study.

Cubic SiC is implanted with carbon ions at 600, 900, 1100 and 1200 °C. X-ray diffraction and transmission electron microscopy revealed the influence of implantation temperature and dose rate on the formation of graphite and diamond precipitates, respectively. The high dose carbon implantation at 600 °C yields graphite already in a textured form. Spherical diamond grains, which are always epitaxial to the SiC, are found in samples implanted at 900 °C or higher. Increasing the dose rate leads to formation of graphite instead of diamond at 900 °C as well. Hence, a critical temperature for diamond evolution exists, which depends on dose rate. Size and shape of the formed diamond precipitates is not influenced by dose rate within the investigated range. Increasing the fluence results in bigger diamond nanocrystals, which are bordered by facets. [Copyright &y& Elsevier]

Nanocrystals of silicon carbide were synthesized inside natural diamond using high dose silicon implantation. In order to retain the diamond structure implantation was done at 900 °C. The samples were subsequently annealed in an rf-heated furnace at 1500 °C for 10 min. X-Ray diffraction (XRD), IR absorption spectrometry and high-resolution cross-sectional transmission electron microscopy (HRTEM) are used to investigate formation and structure of SiC nanocrystallites in the implanted diamond. Raman spectroscopy contributed to trace implantation-induced destruction of the diamond. A first characterization of the electrical properties of the implanted and annealed samples is done by four-point probe measurements. The results indicate a highly conductive, buried layer inside the diamond. This layer contains cubic SiC nanocrystals, which are perfectly aligned with the diamond lattice. However, when fluence exceeds a critical value of 5.3×1017 Si+ cm−2, the diamond is irreversibly damaged and defect conduction type dominates. [Copyright &y& Elsevier]

High-dose carbon implantation (3 × 10[sup 17] and 1 × 10[sup 18] ions/cm²) into cubic SiC on Si was carried out at elevated temperatures (600 to 1200°C) and different dose rates (1×10[sup 13] to 1.5 × 10[sup 14] cm[sup -2] s[sup -1]). Transmission electron microscopy revealed the formation of either graphite or diamond precipitates, depending on the implantation parameters. In all cases, the diamond grains were epitaxial to the SiC lattice, while the graphite was textured. The minimum temperature for diamond formation was 900 °C, while graphite formed at 600 °C. The synthesized phase depends as well on the dose rate; graphite was formed at 900 °C with a high dose rate. Obviously, a critical temperature for diamond formation exists and increases with increasing dose rate. This behavior is explained by the competition between the accumulation and dynamic annealing of radiation defects in the SiC lattice, which acts as a template for diamond nucleation. Diamond grains with diameters as large as 10 nm have been observed after implantation at 1200 °C. [ABSTRACT FROM AUTHOR]

Examines the aluminum carbide formation in silicon carbide (SiC) with high dose of aluminum ion implantation. Properties of SiC for electronic and mechanical applications; Similarities in the aluminum carbide precipitates with the silicon carbide matrix.

Measures the density of amorphous silicon carbide layers by x-ray reflectometry. Comparison to the results of step height measurements; Investigation of density as function of depth using reactive ion etching; Homogeneity of the density reduction across the whole layer thickness.

Investigates the ion-beam-induced recrystallization of amorphous surface layers on single-crystalline silicon carbide substrates. Use of transmission electron microscopy, Rutherford backsetting spectroscopy and channeling; Efficiency of irradiation to reduce the temperature of epitaxial layer regrowth; Nucleation of recrystalline materials.

Natural IIa diamond was implanted at 90 keV to 1x10[sup 15] N[sup +]/cm[sup 2] and subsequently at 150 keV to 3x10[sup 17] Si[sup +]/cm[sup 2] at a temperature of 900 °C. The structure of the implanted diamond region was investigated by high-resolution cross-sectional transmission electron microscopy, Raman, and infrared absorption spectrometry. A buried layer with crystalline 3C-SiC domains in perfect epitaxial relation to the diamond substrate was detected. Amorphization and graphitization were completely prevented by the elevated temperature during the implantation. Resistance measurements demonstrated low electrical resistivity in the implanted regions. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A high dose of 1x10[sup 18] cm[sup -2], 60 keV carbon ions was implanted into single crystalline 6H silicon carbide (SiC) at elevated temperatures. The formation of carbon phases in the crystalline SiC lattice was investigated by cross sectional transmission electron microscopy. An amorphous, carbon rich phase was produced at 300 °C. Precipitates of graphite were obtained at 600 °C, whereas at 900 °C small diamond grains were produced. These grains are in perfect epitaxial relation with the surrounding SiC lattice. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Nanometer-sized SiC precipitates were synthesized at 450 °C in Si by simultaneous dual beam implantation of C+ and Si+ ions and subsequent annealing. The results are compared with those of sequential dual beam implantation and of single beam implantation. Two types of SiC precipitates were found. Precipitates of type I with a diameter of d=4–5 nm consist of 3C-SiC epitaxially oriented with the Si matrix. They were formed already in the as-implanted state and do not grow further during subsequent annealing. The SiC precipitates of type II with d≈10 nm are not oriented with the Si matrix and grow exclusively during the subsequent annealing. The high growth velocity, the misorientation in regard to the Si matrix and the lower concentration of type II precipitates can be explained by the assumption that these precipitates were formed in an amorphous substrate which modifies their interface energy. [Copyright &y& Elsevier]

6H-SiC samples were amorphised by multiple Al implantations at room temperature, in order to study the annealing process. The paper deals with the influence of specific annealing conditions, such as furnace atmosphere and heating rate, on SiC reordering and Al profile. Below a certain deposited nuclear energy, solid phase epitaxy is possible and leads to recrystallisation under precise conditions (high heating rate, silicon partial pressure prescribed). Above it, material etching and dopant losses are observed, even though annealing has proven to be efficient for avoiding surface impairment (due to a specific cleaning process). [Copyright &y& Elsevier]