Black poly-silicon: A nanostructured seed layer for sensor applications

Abstract

Abstract:Nanostructured silicon surfaces like black-silicon (b-Si) are of great interest in current sensor technology. This paper presents an alternative method to fabricate b-Si in poly-silicon thin film prepared on pre-deposited insulation layer in order to open new door to the integration of silicon nanograss in biosensor application as sensing or seed layer. In our experiment, black poly-silicon (BPS) is formed in LPCVD deposited poly-silicon thin film by deep reactive ion etching (DRIE) at cryogenic temperature in SF 6 +O 2 plasma. Etching parameters like temperature, O 2 flow and RF power is varied and morphology of the resultant thin film is analyzed by scanning electron microscopy. The fabricated samples are subjected to a comparative investigation, which contained pillar density, directionality, etch rate and loading effects. The effect of the grain size of poly-silicon layer is analyzed and compared to samples micromachined in single-crystalline silicon (c-Si). We found that fabrication parameters of BPS morphology significantly differ from that of conventional b-Si realized in c-Si substrate. A simple application example of our BPS layer for increasing specific surface area of potential sensors is also demonstrated. As far as we know, this is the first demonstration and systematic study of b-Si fabrication in poly-silicon thin film.

Neurobiochemical changes in the vicinity of a nanostructured neural implant

“…The morphological parameters of the nanostructured poly-silicon surfaces ( nanoSi ) (pillar density, pillar height) were defined from scanning electron micrographs. The heights of the nanopillars were between 520–800 nm and their density was between 18–70 pillars/μm 2 depending on the fabrication parameters of the deep reactive ion etching (DRIE) process 32 . The other three surfaces were also visualised using electron microscopy.…”

“…Two quantitative parameters were used to characterise the physical properties of the surface: pillar density and pillar height. Pillar density corresponds to the number of spot-like contaminations on the surface exposed to ion etching 32 33 normalised to 1 μm 2 . Pillar height refers to the average height of BPS nanopillars, and is also determined by the etch rate of the original layer.…”

“…The advantage of black poly-Si is that its production can be integrated into the fabrication scheme of Michigan type silicon neural microelectrodes, since it is made of LPCVD deposited poly-Si thin film and subsequent nanostructuring in a deep reactive ion etching chamber in SF 6 + O 2 plasma 31 . The nanoscale morphology of a sensor surface can be tailored by tuning the thickness and morphology of the nanopillar seed layer and the fabrication parameters 32 . The effect of the different surface topographies on glial cells and neurons in the vicinity of the implantation is characterised using GFAP and NeuN immunostaining followed by a systematic image analysis.…”

Neural Cell Response to Nanostructured Biosensor Surfaces

“…Our work aims to synthesize bioimplant surfaces with nanoscale patterns using novel combination of micro-and nanomachining techniques [10]. The proposed maskless nanopatterning method can easily be integrated into the fabrication process of neural microelectrodes.…”

Silver hierarchical structures grown on microstructured silicon in chip for microfluidic integrated catalyst and SERS detector

“…Black silicon (BS) is widely researched in the areas of photodetectors, solar cells, and sensors since it has many remarkable properties, such as a large absorption range and a highly effective surface area [1][2][3][4][5] . When its micro/ nano-roughened surface is coated with metal nanoparticles, BS could be utilized for various other applications, such as surface-enhanced Raman scattering (SERS) sensors [6][7][8] .…”