GaN and ZnO freestanding micromechanical structures on silicon‐on‐insulator substrates

Abstract

Using a combination of selective dry etching techniques, surface micro‐machined GaN and ZnO micromechanical structures are demonstrated on silicon‐on‐insulator (SOI) substrates. The dry releasing technique employs a controlled gas phase pulse etching with non‐plasma xenon difluoride (XeF2), which selectively etches the Si overlayer of SOI, thus undercutting the wide bandgap semiconductor material on top. This method prevents crystal damage of overhanging wide bandgap semiconductor mechanical structures. The mechanical properties of these released microstructures are characterized by micro‐Raman spectroscopy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Luminescence Properties of Photonic Crystal InGaN/GaN Light Emitting Layers on Silicon-on-Insulator

“…The fabrication of freestanding GaN microstructures on SOI and bulk Si substrates by wet chemical or dry etching has been previously reported. [18][19][20][21] Here, we used the wet chemical etching step to address the PL properties of undercut PhC LEDs. Figure 2f shows the comparative micro-PL spectra recorded from the freestanding PhC LED layers ͑sample with patterns as shown in Fig.…”