This paper presents a design and simulation of a novel high performance 3D-silicon photodetector for implementing in the low intensity light detection at room temperature (300K). The photodetector is modeled by inspiration of general MEMS fabrication to make a 3D- structure in the silicon substrate using a bulk micromachining process, and based on a complementary metal-oxide semiconductor (CMOS) technology. The design includes a vertical n+/p junction as an optical window for lateral illumination. The simulation is carried out using COMSOL Multiphysics relying on theoretical and physical concepts, and then, the assessment of the results is done by the numerical analysis with SILVACO (Atlas) device simulator. Light is regarded as a monochromatic beam with a wavelength of 633nm that is placed 1μm far from the optical window. The simulation is considered under the reverse bias dc voltage in the steadystate. We present photocurrent-voltage (Iph-V) characteristics under different light intensities (2… 10[mW/cm2]), and dark current-voltage (Id-V) characteristics. Comparative studies of sensitivity dependence on the dopant concentration in the substrate as an intrinsic region are accomplished utilizing two different p-type silicon substrates with 1×1015 [1/cm3] and 4×1012 [1/cm3] doping concentration. Moreover, the sensitivity is evaluated with respect to the active substrate thickness. The simulated results confirmed that the high optical sensitivity of the photodetector with low dark current can be realized in this model.
Many applications in micro and nanotechnologies require micron-sized components, capable of positioning in
ranges of sub-micrometers to a few microns. This paper reports on the design, fabrication and characterization procedure
of an electrostatically actuated polymeric Nano-precision micro z-stage. Due to its ease of fabrication and great variety
of functionalities, polymers have become an important material in micro fabrication technology. In contrast to
piezoelectric stages, polymeric micro stage has a comparatively simple and cost effective fabrication procedure.
Furthermore, low Young's Modulus of polymers made them a suitable basic material in comparison with their traditional
counterparts. In this paper, SU-8 photoresist was used as the construction material and the photolithography technique
were used to realize the stage. SU-8 with its low Young's modulus (5 GPa), has a higher tendency for bending,
compared to, for example, silicon nitride (150-350 GPa). These properties make the SU-8 polymer, suitable for various
In this paper, we have introduced a method for design and fabrication of a micro-windmill based on SU-8 photoresist
that is rotated by gas flow. This device is used for measuring gas flow by assessment of rotational speed of the microwindmill.
The flow-meter sensitivity is influenced by different parameters such as number of blades and dimension of
the windmills. Therefore, we have tried to experimentally reduce the dimensions and increase of the number of blades to
obtain the higher sensitivity in measuring gas flow. An experimental setup is arranged to measure the rotational
frequency of the windmill as a function of gas flow with optical methods.
In this paper we have explained a new method for measuring the cantilever displacement using both reflective
and interferometric properties of the cantilever. In our method, a Laser light is shone on the cantilever, and the reflected
pattern is monitored by a commercially available CCD. Due to the micrometer dimensions of the cantilever which was
smaller than the spot size of the laser, the laser beam would be reflected by both substrate and the cantilever's surface,
and this will produce an interference pattern on the screen. In this configuration, a displacement in the cantilever will
reflect the light in a different angle and also changes the optical path difference between the reflected light from the
cantilever and substrate. The overall result of these two effects would be a total displacement of the pattern, which could
be simply measured using a CCD. Finally, by taking both effects into consideration,, the cantilever's displacement could
be measured. For testing this technique different cantilevers were fabricated and were electrostatically actuated. In this
method, displacements as small as 10nm were possible to measure.