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This work reports on the nanomechanical metrology of vertically aligned gallium nitride micropillar arrays with high homogeneity and well‐controlled geometry. The GaN micro‐building blocks are top‐down fabricated by combining photolithography, inductively coupled plasma dry reactive ion etching (ICP‐DRIE) with SF6/H2 gases, and post‐wet chemical etching treatment by a KOH‐based solution. A nanoindenter with a three‐sided pyramid Berkovich tip is employed to precisely measure the mechanical properties of the GaN micropillars directly from their top surfaces, hence an additional preparatory work to transfer them on a foreign substrate is not necessary. From the obtained experimental results, the insight of the indentation pop‐in phenomenon on the micropillars is carefully investigated. Besides, a confocal laser scanning microscope (CLSM) and an atomic force microscope (AFM) are utilized to confirm the high homogeneity of the micropillar arrays before indentation and to characterize the morphologies of their top surfaces after stress relaxation, respectively. Therefore, the obtained experimental results can be employed as the prior knowledge to be compared with the bulk counterparts, in which the GaN micropillars can be further developed for mechanical force sensors, since the performed measurement techniques have provided the existent mechanical circumstance of the microstructures when a vertical force is applied.

Vertically aligned 3D gallium nitride (GaN) nanowire arrays with sub-50 nm feature sizes were fabricated using a nanosphere lift-off lithography (NSLL) technique combined with hybrid top-down etching steps (i.e., inductively coupled plasma dry reactive ion etching (ICP-DRIE) and wet chemical etching). Owing to the well-controlled chemical surface treatment prior to the nanobead deposition and etching process, vertical GaN nanowire arrays with diameter of ~35 nm, pitch of ~350 nm, and aspect ratio of >10 could be realized using 500 nm polystyrene nanobead (PN) masks. This work has demonstrated a feasibility of using NSLL as an alternative for other sophisticated but expensive nanolithography methods to manufacture low-cost but highly ordered 3D GaN nanostructures.

Sensor strain digunakan untuk mengukur perubahan strain akibat stress pada suatu bahan. Dalam penelitian ini, telah dirancang sensor strain menggunakan fiber optik dari bahan dielektris plastik dengan teknik pencacatan. Teknik yang dipakai adalah untuk melihat perubahan intensitas cahaya yang terdeteksi sebagai akibat dari stress yang diterima fiber optik. Pengamatan dalam perancangan sensor fiber optik menggunakan PC mikroskop sehingga struktur permukaan fiber yang kecil dan halus dapat terlihat. Untuk mengetahui besaran strain akibat stress yang terukur dibutuhkan sumber cahaya laser, fotodetektor, rangkaian amplifier, modul akuisisi data (DAQ) dan PC. Evaluasi hasil perancangan sensor dilakukan dengan uji tarik (tensile) fiber optik yang diletakkan pada spesimen menggunakan mesin universal tensile meter (UTM).

Silicon and germanium pillar structures (i.e., micro-and nanowires) were fabricated by a top-down approach including nanoimprint lithography and cryogenic dry etching. Various etching parameters were tested to ensure a reliable fabrication process. The impression of nanomechanical properties of such 3-D structures were extracted experimentally by nanoindentation showing promising and comparative results to utilize such nanostructures as small force artefacts.

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Phosphorus and boron diffusion in silicon at temperatures between 900 and 1050 °C was studied both in bulk and nanostructured samples by means of scanning spreading resistance microscopy. The dopant diffusion from highly doped silicon substrates into 300–1200 nm diameter natural silicon nanopillars is clearly retarded compared to dopant diffusion in the bulk material. A three-dimensional solution of Fick’s equation enables a better understanding of dopant diffusion processes in silicon nanostructures, including all participating point defects. The observed decrease of diffusivity by 20%–50% can be explained by the injection of vacancies at the sidewalls of the pillar. The results do not provide any evidence on a possible change in point defect properties or fundamental diffusion processes in silicon nanostructures with respect to bulk silicon.

In this paper we present an investigation of the influence of nanoindentation location on the top surface of silicon micro-pillar. This silicon micro-pillar array which will be employed as a micro force sensor array based on three-dimension silicon (3D Si) structures, is fabricated by near UV nanoimprint lithography (NIL) technique and etched by Cryogenic Inductively Coupled Plasma (ICP) sequentially. To determine its mechanical properties, those micropillars are measured by instrument indentation testing (IIT) to obtain its hardness and reduced modulus. For the measurement, a Berkovich diamond indenter is utilized to penetrate a single and also multiple point indentations on a micro-pillar surface. Afterwards, these results are compared to the indentation at the central point of the tested pillar and Si bulk as its reference to examine the influence of different probing locations on the measured reduced modulus and hardness.