In this article, the physico-chemical and electrochemical conditions of through-silicon via formation were studied. First, macropore arrays were etched through a low doped n-type silicon wafer by ...anodization under illumination into a hydrofluoric acid-based electrolyte. After electrochemical etching, ‘almost’ through-silicon macropores were locally opened by a backside photolithographic process followed by anisotropic etching. The 450 × 450-μm² opened areas were then selectively filled with copper by a potentiostatic electrochemical deposition. Using this process, high density conductive via (4.5 × 10
5
cm
−
²) was carried out. The conductive paths were then electrically characterized, and a resistance equal to 32 mΩ/copper-filled macropore was determined.
The rising market of flexible nomadic systems requires the development of cost-efficient processes and high performance devices. In this study, we report on a simple technique to integrate ...micro-inductors on a low-loss 50 μm-thick porous silicon membrane. The etching of porous silicon was performed according to a two-step anodization process in order to create a fragile interface between the silicon substrate and the porous layer. Then, the integration of radio-frequency micro-inductors followed a conventional microelectronic procedure. At the end of the process, the membranes with the devices were mechanically peeled-off from bulk silicon, providing the possible means to recycle the silicon substrate for subsequent devices integration. S-parameters measurements showed a significant improvement of the quality factor and the resonant frequency after the substrate removal. This result is promising for the near future of ultra-thin flexible electronic devices.
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•Simple process to obtain ultra-thin flexible porous silicon membranes.•Integration of micro-inductors on low-loss 50 μm-thick porous silicon membranes.•High quality factor micro-inductors.
Mesoporous silicon can be used as isolating substrate for the integration of radiofrequency (RF) passive devices. The higher is the porous silicon (PS) thickness, the better are the RF performances. ...However, an increase of PS thickness induces a raise of strain in the substrate.
In this work, the strain of 6 inches PS substrates which has been generated during electrochemical etching and post anodization annealing steps are studied. It is shown that, if the anodization process is not well-controlled, the consequences can be cracks of the PS layer or a high wafer curvature which prevents device from integration with a standard process. It is also demonstrated that different kinds of defects due to PS stress can be also observed on full wafer PS layers and localized PS substrates as well.
•Electrochemical anodization of large area Si wafers is studied.•Process steps involved in stress generation into wafers are identified.•Complex RF devices were integrated on localized porous silicon regions.
The silicon/porous silicon (PS) hybrid substrate is an interesting candidate for the monolithic integration of radiofrequency (RF) circuits. Thus, passive components can be integrated on the ...insulating PS regions close to the active devices integrated on silicon. Regarding silicon, hybrid substrates allow the improvement of RF circuits performances. To demonstrate it, coplanar waveguides have been integrated on glass, silicon, and localized PS substrates. The characterization results show that the substrate losses are reduced with PS.
This paper presents a novel frequency reconfigurable patch antenna where the tunable element is not only integrated in a silicon substrate but also co-designed and manufactured in the same process ...flow as the antenna itself. The active element is based on a N + PP + junction which acts as a switch (OFF- and ON-states). With a low bias voltage (- 1.2 V), one radiated slot is short-circuited to the ground plane on the whole antenna width allowing a tuning frequency of the patch antenna. A demonstrator, which has been characterized and manufactured validates the co-designed method of the resonant frequency antenna. It switches from 11.6 GHz to 17.4 GHz.
For the first time, inductors were integrated on porous silicon carbide to study the effect of this substrate on radio-frequency (RF) performances. n-Type heavily doped 4H-SiC substrates were ...anodized in an HF-based electrolyte to produce 6- and 15-μm-thick porous layers. An improvement of the quality factor was demonstrated on porous SiC with regard to SiC bulk. This promising result shows the decrease of substrate losses at the high frequencies with the porous SiC substrate. Thus, porous SiC could have an interest for the integration of RF power devices.
This paper presents a novel reconfigurable polarization patch antenna designed on a silicon substrate and using integrated semiconductor distributed doped areas (ScDDAs) as active elements. The ...antenna is able to commute from a circular to a linear polarization. The co-design between the antenna and the ScDDAs results in a monolithic integration of the active elements in the substrate. This method allows to optimize the global performances in the circular and linear polarizations thanks to the flexibility of the doped area shape and position. A demonstrator is proposed from the simulations to the measurements and validates the proof of concept.
This paper deals with a patch antenna presenting a reconfigurable polarization using semiconductor distributed doped areas (ScDDAs). This on-chip antenna offers a switch able polarization between two ...linear ones. The monolithic integration of the ScDDAs as active elements directly in the substrate avoids additional components and gives design flexibility. The antenna and the ScDDAs are co-designed and manufactured in a same process flow. The commutation is achieved with a DC bias of − 2.2 V. The measured results fit well with the simulated ones.
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