We propose the application of GaNAs as a novel material fabricated on a Si wafer. It is a direct-transition type semiconductor, and can be lattice-matched to Si. Therefore, it is valid for use in the active region of light-emitting devices fabricated on Si. In this letter, GaNAs with a low N content is grown on a GaAs wafer to explore the gas-source molecular beam epitaxy under which a N radical is used as the N source. As a consequence, GaNAs with a N content up to 1.5% is grown, even though the conductance of the N-radical beam cell is fixed at a very low value. The bowing parameter of the bandgap is experimentally evaluated at 18 eV.

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One-dimensional SiO 2 deeply etched periodic structures were fabricated. The fabrication process was based on an anisotropic Si etching, followed by a direct oxidation of the etched Si structure. The obtained submicron-scale SiO 2 periodic structure had an ultrahigh aspect ratio of 16 for the etched space and an etching depth of as large as 12.5 m. The etched depth was limited only by the etching mask. Therefore, increasing the mask thickness, or replacing it with a much harder mask material, should result in a much larger aspect ratio and etching depth. This structure also had an excellent vertical profile of less than 0.5°and extremely smooth surfaces of only 0.6 nm rms suitable for use in various applications, particularly in photonics fields that require a broad band performance, ranging from ultraviolet to near infrared.

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