Scanning electron microscopy of the surfaces of ion implanted SiC

Abstract

This paper gives a brief review of radiation damage caused by particle (ions and neutrons) bombardment in SiC at different temperatures, and its annealing, with an expanded discussion on the effects occurring on the surface. The surface effects were observed using SEM (scanning electron microscopy) with an in-lens detector and EBSD (electron backscatter diffraction). Two substrates were used, viz. single crystalline 6H-SiC wafers and polycrystalline SiC, where the majority of the crystallites were 3C-SiC. The surface modification of the SiC samples by 360 keV ion bombardment was studied at temperatures below (i.e. room temperature), just at (i.e. 350 °C), or above (i.e. 600 °C) the critical temperature for amorphization of SiC. For bombardment at a temperature at about the critical temperature an extra step, viz. post-bombardment annealing, was needed to ascertain the microstructure of bombarded layer. Another aspect investigated was the effect of annealing of samples with an ion bombardment-induced amorphous layer on a 6H-SiC substrate. SEM could detect that this layer started to crystalize at 900 °C. The resulting topography exhibited a dependence on the ion species. EBSD showed that the crystallites forming in the amorphized layer were 3C-SiC and not 6H-SiC as the substrate. The investigations also pointed out the behaviour of the epitaxial regrowth of the amorphous layer from the 6H-SiC interface. johan.malherbe@up.ac.za

The effects of helium, strontium, and silver triple ions implanted into SiC

“…If one assumes that the critical amorphization of SiC is 0.3 dpa [ 31 ], all implantations will completely amorphized SiC at room temperature. However, our implantations were performed at temperatures well above the critical amorphization temperature of SiC [ 26 , 32 ]. Therefore, the samples were not expected to be fully amorphized under the implantation conditions used in this study.…”

“…Si–Si homonuclear band in the range 400–600 cm −1 , and the C–C homonuclear band in the range 1100–1700 cm −1 [ 25 , [33] , [34] , [35] ]. The lack of amorphization is due to the implantation temperatures (600 °C and 350 °C) that are greater than the critical temperature of amorphization [ 26 , 32 ]. In both Raman spectra of dual and triple implanted SiC, the homonuclear bonds especially the Si–Si are dominant, which agrees with TEM result of the as-implanted sample in Fig.…”

Enhanced thermal stability by introducing TiN diffusion barrier layer between W and SiC

“…Silicon carbide (SiC) is a refractory compound semiconductor material that has many unique and desirable electrical, mechanical, and chemical properties including high melting point, low density, good mechanical behavior, resistance to oxidation at high temperature and chemical inertness to corrosive media. In addition to its application in high power electronic devices with the ability to operate at temperatures as high as 600°C, [1][2][3] SiC has several other high temperature applications including nuclear materials, [4][5][6] reinforced composites, 7 and the hot cell of thermionic energy converters. 8,9 Tungsten (W) is one of the preferred ohmic contact metals on SiC for semiconductor device applications due to its high melting point (3400°C), high temperature stability, inherent heat resistance, and high thermal conductivity, as well as excellent corrosion and abrasion resistance.…”

“…Silicon carbide (SiC) is a refractory compound semiconductor material that has many unique and desirable electrical, mechanical, and chemical properties including high melting point, low density, good mechanical behavior, resistance to oxidation at high temperature and chemical inertness to corrosive media. In addition to its application in high power electronic devices with the ability to operate at temperatures as high as 600°C, SiC has several other high temperature applications including nuclear materials, reinforced composites, and the hot cell of thermionic energy converters …”

Surface and interface structural analysis of W deposited on 6H–SiC substrates annealed in argon

“…3 Silicon carbide is one of the materials used in a vast number of applications such as a wide band-gap semiconductor, 4,5 nuclear material, [6][7][8] reinforced composite, 9 etc. This is because of its exceptional properties like high corrosion resistance, high thermal stability, high thermal conductivity, high breakdown electric eld strength, etc.…”