Fabrication of Silicon Carbide Micropillar Arrays from Polycarbosilanes

Abstract

Periodic patterns of silicon carbide (SiC) micropillars of 18 μm in length and 2 μm in diameter with a hexagonal morphology and an areal number density of micropillars of 6 × 104 mm−2 were fabricated from a mixture of two different polycarbosilane ceramic precursors. The polycarbosilanes (PCS) were molded into polydimethylsiloxane (PDMS) micromolds processed from a silicon wafer master. After cross‐linking between 200° and 400°C, debonding from the elastomeric PDMS mold yielded freestanding structures of PCS micropillars. Due to the low stiffness of cross‐linked PCS (E∼2.5 GPa), surface adhesion forces might result in the deformation of the micropillars into ordered domains. The PCS micropillar arrays were pyrolyzed in inert atmosphere at 900° and 1500°C to yield amorphous and nanocrystalline SiC (β‐SiC) with crystallite sizes in the range of tenths of micrometers, respectively. The formation of domains due to instability of micropillars with a high aspect ratio might be of specific interest for electrical engineering and catalytic applications.

Deterministic placement of ultra-bright near-infrared color centers in arrays of silicon carbide micropillars

“…Micropillars in other materials have been successfully used as photonics structures designed to improve the photoluminescence performance of quantum dots for strong coupling of the emission with the photonics cavity, high photon-extraction efficiency and SPS on-demand generation with near-unity indistinguishability [41–43]. Silicon carbide micropillars have been used in unrelated mechanical property studies in the past [44–45]. Towards the abovementioned goals, a scalable approach for the design and fabrication of photonics wafers to control the local density of states of the emitters is needed.…”

Crack‐Free Drying of Ceramic Microparts on a Hydrophobic Flexible Polymer Substrate Using Soft Lithography

“…Ceramic microparts and micropatterned surfaces have found various applications in the field of microelectromechanical systems (MEMS), for example as microphotonic crystals, as micropillar sensors, and as dielectric resonator microparts . However, mass production of ceramic microparts is still a great challenge.…”

“…Soft lithography, developed by Whitesides and co‐workers, provides a set of net‐shaped and low‐cost methods for producing complex‐shaped ceramic microparts . In a soft lithographic method, a polymeric precursor (known as polymer‐derived ceramic, PDC) or a well‐dispersed ceramic suspension is often cast into microfabricated poly(dimethylsiloxane) (PDMS) molds to form green microparts, which undergo subsequent sintering to obtain the final microparts. To form green microparts, the suspensions need long processing times for gelation and drying, whereas PDCs do not.…”

Preparation of Refined SiC Patterns from Imprinting of Partially Cross‐Linked Solid Polycarbosilane

“…Polymeric precursors have been recognized as a promising candidate for the fabrication of ceramic nano/micro‐structures. Refined SiCN, SiC, and SiO 2 microstructures were synthesized from a capillary‐condensation process using liquid polycarbosilane as the raw material and polydimethylsiloxane elastometric stamp as the master mold …”

“…Refined SiCN, SiC, and SiO 2 microstructures were synthesized from a capillarycondensation process using liquid polycarbosilane as the raw material and polydimethylsiloxane elastometric stamp as the master mold. [17][18][19][20][21] In this study, refined SiC patterns were successfully produced from an imprint lithography method using solid polycarbosilane (PCS) as SiC precursor and Si mold as the master structures. Cracking was effectively prevented by precuring PCS under moderate oxidation treatment, which induces partial cross-linking and a degree of thermoplasticity to the PCS solids.…”