A Combination of Metal Assisted Photochemical and Photoelectrochemical Etching for Tailored Porosification of 4H SiC Substrates

Abstract

Porous 4H-SiC layers were prepared with a tailored sequence of metal assisted photochemical etching (MAPCE) and photoelectrochemical etching (PECE) steps. Porous layers resulting from MAPCE provided initiation sites for a subsequent PECE process. Finally, the porosity of the porous layers was increased to the desired degree with a second MAPCE step. By applying this sequence, the problem of skin and cap layer formation occurring during pure PECE is avoided. In addition, layers with a homogeneous porosity depth profile are obtained, which is not possible when only pure PECE is applied.

Producing Silicon Carbide Micro and Nanostructures by Plasma‐Free Metal‐Assisted Chemical Etching

“…[43,44] The generally accepted open circuit hν-MacEtch reaction of SiC involves three steps. [38,42] The first two, associated with carrier generation, are the product of two reduction reactions, both of which are reliant on UV light generating free electrons;…”

Voltage-Controlled Anodic Oxidation of Porous Fluorescent SiC for Effective Surface Passivation

“…In porous fabrication, anodic oxidation is a popular method for etching SiC, on account of its extreme chemical stability. Generally, the optical properties of porous SiC are largely determined by the morphological properties of pores [ 18 , 19 ], which are mainly affected by current density, compositions of both the etching solution, and the exposed surface (Si or C) during the anodic oxidation process [ 20 , 21 ]. A non-uniform distribution of porous structures was commonly observed as a consequence of porous depth when the anodic oxidation was conducted under a direct or pulsed constant-current mode [ 15 , 22 ].…”

Effective optimization of surface passivation on porous silicon carbide using atomic layer deposited Al2O3

“…6,7 The morphology of porous SiC is usually determined by the experimental parameters such as the electrical current density, the composition of the etching solution and sample termination surface (Si or C) exposed to the etching solution. 8 Although porous SiC is an attractive wavelength converter, the luminescence of porous SiC is not very stable because of the large sensitive surface area. Even exposure to ambient air can cause degradation of PL due to the surface oxidation.…”