Silicon‐29 Solid‐State MAS NMR Investigation of Selective Area Laser Deposition Silicon Carbide Material

Abstract

The microstructure of silicon carbide fabricated from the gas‐phase‐based, laser‐driven selective area laser deposition (SALD) process has been characterized by X‐ray diffraction and solid‐state 29Si NMR techniques with magic angle spinning (MAS). X‐ray patterns reveal the characteristic spectrum of pure ß, cubic silicon carbide polytype while NMR shows a ß‐SiC pattern with additional peaks. To determine the source of the extra peaks, a comparative evaluation of commercially available silicon carbide powders, both alpha‐ and ß‐SiC, was undertaken with NMR. Spin‐lattice relaxation time measurements (T1) were also carried out to determine the polytype morphology of the SALD deposit. The results showed an NMR spectrum that appears to be a combination of alpha and ß polytypes. Microtwinning is advanced as a possible explanation for this phenomenon.