Features of the structure of a porous silicon carbide layer obtained by electrochemical etching of a 6H-SiC substrate

Formation of Bare Porous Surface on 6H-SiC Substrates by Photo-Electrochemical Etching

“…Although it should be discussed comprehensively in porous formation mechanism [20][21][22] in future, we speculate in this stage that the imbalance in overall reaction and transport may affect to the skin appearance because the reactants and the products must transport in very narrow and long pores combining the bottom of the pore and the outer. 23) In our limited measurements of SIMS and Raman spectra for the skin layers, the composition was richest in carbon, followed by silicon and lowest in oxygen, and two Raman shifts near to 1300 cm -1 and 1600 cm -1 , seemed to be D-band and G-band in amorphous carbon 24) , were also observed. The skin layers peeled off were colored transparent yellow-brown, and their flakes charged up easily in air and by electron beam, too.…”

“…Although the mechanism involved should be discussed comprehensively when considering pore formation, [20][21][22] we currently speculate that the distribution of chemical species along the depth of a pore may cause the appearance of the skin layer because the reactants and the products must be transported in very narrow and long pores linking the bottom of the pore and the exterior. 23) From our limited measurements of Secondary Ion Mass Spectrometry (SIMS) and Raman spectra for the skin layers, we found that carbon was the most common element, followed by silicon, with oxygen having the lowest concentration. Two Raman shifts near 1300 and 1600 cm À1 that appeared to represent a D-band and a G-band, respectively, in amorphous carbon 24) were also observed.…”

Early Attainments of Porous Silicon Carbide Technology: a Bibliographic Digest

“…W. Shin with co-workers reported that not only parameters of anodization defined the type of resulted porous structures, but also the doping level of the initial SiC crystals did [34]. Similar results of detailed micro-structural studies of PSC prepared on the basis of single-crystal SiC samples with 4H-and 6H-polytypes were published in a series of works by Zangooie et al [35][36][37][38][39] and groups of researchers from the Ioffe Institute (Russia) [40][41][42][43]. On the basis of them, one generalizing conclusion can be drawn.…”

Review—Progress in Electrochemical Etching of Third-Generation Semiconductors

“…37 In addition, active agents, such as Hexadecyl trimethyl ammonium chloride (CTAC), ammonium dodecyl sulfate (ADS), Triton X-100 and acetic acid, can improve the uniformity of the morphology, 38 while ultrasonic assistance can increase the etch rate accelerating the exchange of reactive substances. 39 In addition to processing micro-nano structures, Sorokin et al 40 also obtained an amorphous C-rich layer on the sample surface by anodic oxidation etching of 6H-SiC. This work was supplemented by Senthilnathan et al 41 who used HF with different organic solvent mixtures as electrolytes, and investigated the effects of polar facets, surface tension, density, and viscosity on the etching process.…”