(a) Measured spectrum showing the mode structure of an L9-PCM; insets show FDTD simulations with the |E|2 mode profile of the first four modes. (b) SEM image of an L9-PCM designed for emission in the 1.3 μm telecom window.
Fabrication procedure for GaAs based L9-PCMs. (a) EBL and developing of ZEP-520A positive resist, (b) RIBE based on CHF3/N2 to transfer the pattern to the SiOx hard mask, (c) ICP–RIE based on BCl3/N2 to transfer the pattern to the active GaAs slab, and (d) removal of the Al0.7Ga0.3As sacrificial layer and remaining SiOx layer with diluted HF to suspend the structures. (e) Tilted view of the final structure.
(a) Impact of the partial N2 flux content on the quality factor (Q) of the PCM fundamental mode in an L9. The error bars represent the range of the Q measured for series with identical fabrication parameters; insets with SEM images show the holes-cross section after the ICP etching for 0.55 (bottom) and 0.65 (top) partial content of nitrogen; the shape and roughness for the highest and lowest Q-factors obtained with nitrogen flux content 0.65 (top) and 0.55 (bottom), respectively. The dashed line represents a guide to the eye. (b) Detail of the line shape for a measured high Q (Q ∼ 30 000) fundamental mode of an L9-PCM fabricated with the optimum partial nitrogen flux content (0.65). The line represents the best Lorentzian fit corresponding to the experimental data.
Observation of flakes; (a) under specific conditions, flakes can be observed through the membrane during SEM inspection as shadowed areas, (b) flakes observed through the openings practiced around the PCM structure, (c) close-up of the flakes revealing the crystallographic morphology of the flakes, (d) opened area with low density of flakes to analyze their composition, and (e) EDAX corresponding to the regions indicated in (d) and showing the elements found in the material outside (top) and within (bottom) the flakes.
Control of the density of flake residuals; (a) 1:10 hydrofluoric dilution yielding slow lateral etch rate (∼1 μm/min) of the sacrificial layer and high density of residual flakes. (b) 1:3 hydrofluoric dilution yielding a rapid etch (∼12 μm/min) of the sacrificial layer that removes most of the flake residuals.
Calculated optical properties for the L9-PCM with a = 350 nm, r = 0.28a, and d = 190 nm. The e-label refers to the even symmetry of the modes.
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