Formation of Aligned α-Si3N4 Microfibers by Plasma Nitridation of Si (110) Substrate Coated with SiO2

Plasma nitridation of an amorphous SiO2 layer on Si (110) substrate can form well-aligned alpha-Si3N4 crystallites in fibrous morphology. Nitriding is performed at a temperature in the range of 800-1000 & DEG;C by using microwave plasma with a gas mixture of N-2 and H-2. Raman spectroscopy shows the characteristics of an alpha-Si3N4 phase without other crystalline nitrides. As shown by scanning electron microscopy, the formed alpha-Si3N4 microfibers on the Si substrate can be in a dense and straight array nearly along with Si < 11 over bar 0 >, and can have a length over 2 mm with a diameter in the range of 5-10 mu m. Structural characterization of scanning transmission electron microscopy in cross section view reveals that the elongated alpha-Si3N4 crystallites are formed on the surface of the nitrided SiO2/Si (110) substrate without any interlayers between Si3N4 and Si, and the longitudinal direction of alpha-Si3N4 appears mainly along < 112 over bar 0 >, which is approximately parallel to Si < 11 over bar 0 >.

Automated summary

Plasma nitridation of an amorphous SiO2 layer on Si (110) substrate can produce well-aligned alpha-Si3N4 crystallites in fibrous morphology, with a dense and straight array along Si<110>. The formed alpha-Si3N4 microfibers have a length over 2 mm with a diameter in the range of 5-10 μm, and are mainly oriented along <1120>.