Aufsatz in einer Fachzeitschrift
Novel low-cost and simple fabrication technology for tunable dielectric active and passive optical air-gap devices

Details zur Publikation
Tarraf, A.; Daleiden, J.; Irmer, S.; Römer, F.; Prott, C.; Ataro, E.; Hillmer, H.; Fuhrmann, T.; Spehr, T.; Salbeck, J.
Proceedings of SPIE

Zusammenfassung, Abstract
A novel low cost technology for fabrication of micro-opto-electro-mechanical devices based on plasma enhancedchemical vapor deposition (PECVD) of dielectric materials is presented. Applying surface micromachining, we producesuspended dielectric membranes and cantilevers by involving a common photo resist as sacrificial layer. The intrinsicstress in the layers is adjusted using an interlacing of high (13.56MHz) and low (130kHz) plasma excitation frequenciesin the PECVD. A diffraction image method and microstructures are used for the homogeneous stress evaluation. Thestress of silicon nitride can be varied in a wide range between +850MPa compressive and –300MPa tensile and nodependence of the frequency on silicon dioxide intrinsic stress is noticed. Depending on lateral design and gradientstress variation, Fabry-Pérot filter membranes with radius of curvature (ROC) between –1.7mm and 51mm as well ascavity lengths between 2.3μm and 13.5μm are implemented. Thus, convex, concave and plane membranes areproduced. Furthermore, a thermally tuned air-gap Fabry-Pérot filter with 8nm FWHM and a tunability of 15nm/mA isfabricated. Strategies of combining these filters with organic laser materials are developed. For this purpose, molecularglasses capable of amplified spontaneous emission (ASE) are chosen, e.g. the molecular glass 4-Spiro2 which shows anamplified spontaneous emission line at a low threshold of 3.2μJ/cm2 pump laser power density.

Zuletzt aktualisiert 2019-25-07 um 12:57