Fabrication and transfer printing based integration of free-standing GaN membrane micro-lenses onto semiconductor chips
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2022-11-08 |
| Journal | Optical Materials Express |
| Authors | Nils Kolja Wessling, Saptarsi Ghosh, Benoit Guilhabert, Menno J. Kappers, A. Hinz |
| Institutions | University of Strathclyde, Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology |
| Citations | 11 |
Abstract
Section titled “Abstract”We demonstrate the back-end integration of optically broadband, high-NA GaN micro-lenses by micro-assembly onto non-native semiconductor substrates. We developed a highly parallel process flow to fabricate and suspend micron scale plano-convex lens platelets from 6” Si growth wafers and show their subsequent transfer-printing integration. A growth process targeted at producing unbowed epitaxial wafers was combined with optimisation of the etching volume in order to produce flat devices for printing. Lens structures were fabricated with 6 − 11 µm diameter, 2 µm height and root-mean-squared surface roughness below 2 nm. The lenses were printed in a vertically coupled geometry on a single crystalline diamond substrate and with µ m-precise placement on a horizontally coupled photonic integrated circuit waveguide facet. Optical performance analysis shows that these lenses could be used to couple to diamond nitrogen vacancy centres at micron scale depths and demonstrates their potential for visible to infrared light-coupling applications.