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A generalized foundry CMOS-MEMS platform suited for integrated micromechanical resonator circuits have been developed for commercial multi-user purpose and demonstrated with a fast turnaround time and a variety of design flexibilities for resonator applications. With this platform, different configurations of capacitively-transduced resonators monolithically integrated with their associated amplifier circuits, spanning frequencies from 500kHz to 14.5MHz, have been realized with resonator Q's around 2,000. This platform specifically featured with various configurations of structural materials, different arrangements of mechanical boundary conditions, large transduction area, well-defined anchors, and performance enhancement scaling with IC fabrication technology, offers a variety of flexible design options suited for sensor and RF applications.

This study reports a simple approach to implement a flexible CNTs tactile sensor to enable the detecting of normal and shear forces. The merits of the presented tactile sensors are as follows, (1) embedded patterned CNTs into polymer using simple Si-substrate molding process, (2) 3D distributed CNTs enable the detection of shear and normal forces, and (3) 3D polymer structure by molding as a tactile-bump. In applications, the CNTs are grown and patterned on bulk-micromachined Si substrate with 3D surface profile. After polymer molding, the 3D distributed CNTs are successfully transferred onto a flexible PDMS with 3D tactile-bump. With proper CNTs pattern designs, the tactile sensor has a sensitivity (linearity) of up to 20.95%/N (R2=0.93) for normal load, and up to 95.24%/N (R2=0.95) for shear load.

This study establishes the polymer-stacking and metal-electroplating processes on Si-substrate to implement a flexible and transparent substrate with alignment mesa, distributed though-hole-vias, and multi-layer electrical routings. This process is especially useful for 3D integration of micro optical components on flexible substrate. The integrated chips can be further protected and sealed by an additional parylene coating. More micro-optical components can also be vertically integrated by additional polymer molding. To demonstrate the feasibility of this approach, LED chips are bonded and sealed in flexible substrate, and the polymer microlens is further integrated with the lighting chips using molding process. The lighting of packaged LED chips is demonstrated in both air and water.

This study presents a novel thermal isolation component “polymer joint” to reduce the current and heat flow (by conduction) between micro thermal actuators. An optical stage consisted of V-beam thermal actuators for optical-tracking and thermal-driven focal-length tunable micro polymer lens for optical-focusing is employed to demonstrate the present concept. To overcome the thermal coupling of these two actuators by heat-conduction, the two components fabricated by SOI wafer (Si∼150W/m-k) are connected by the low thermal conductivity joints (polymer∼0.2W/m-k). The displacement provides by the V-beam actuator is about ±13µm. The temperature difference is about 80°C measurement by infrascope. The variation of micro lens radius of curvature is about 1%.

Integrated CMOS-MEMS array resonators have been demonstrated that takes advantage of pull-in effect to surmount limitations of CMOS foundry process and attains electrode-to-resonator gap spacing at a deep-submicron range, leading to much smaller motional impedance compared to conventional CMOS-MEMS technologies, while possessing unique frequency tuning capability by modulating their mechanical boundary conditions. With the increase of applied dc-bias which simultaneously serves for functions of pull-in and resonator operation, the upward frequency shift of resonance caused by boundary condition (“BC”) change offers opposite tuning mechanism to well-known effect of electrical stiffness. As a result, frequency variation induced by BC-modulation and electrical-stiffness would yield a frequency-insensitive region under a certain dc-bias.

This study implements a novel lighting chip with tunable radiation pattern. The lighting chip consists of polymer-dispersed liquid crystal (PDLC) microprism array, LED, and Si-carrier. By integrating the characteristics of microprism and the scattering/transmitting modes of PDLC, the PDLC-microprism enables the tuning of radiation pattern when applying voltage. The lighting chip with PDLC-microprism has the following advantages, (1) no moving parts are required to tune the radiation pattern, (2) the shape of PDLC-microprism array can be easily changed by molding processes, and (3) the fabrication and packaging are performed at low temperature and the damage to PDLC is prevented.

This study establishes a batch fabricated process to implement and monolithically integrate CNTs (carbon nanotubes) based physical sensors. In this process, vertically aligned CNTs (not horizontally aligned or mixed CNTs) are grown and patterned on Si-wafer as sensing elements, and also integrated with MEMS (microelectromechanical systems) structures. The mechanical deformation and temperature change is thus detected by the resistance change of such CNTs sensing elements. In applications, the CNTs-based pressure sensor and temperature sensor are monolithically fabricated on a chip. Preliminary measurements indicate the presented CNTs-based piezoresistive pressure sensor has a gauge factor of ∼20, and the sensitivity of CNTs-based temperature sensor is 0.19/°C.

This study reports a flexible CNTs (carbon nanotubes) photosensor array for light detection. In this device, the CNTs for light detection are embedded into the flexible Parylene-C film. The batch fabricated flexible CNTs photosensor array using the micromachining processes is implemented. The measurements show the output photocurrent varies linearly with the input light intensity. Moreover, the quantum efficiency of CNTs is about 0.063% in atmospheric pressure, and becomes 1.93% in vacuum of 3mTorr. In summary, the sensitivity of presented device can be further increased for 2 orders by vacuum package. Finally, the position detection of light beam using presented device has also been demonstrated.

This study reports the design and implementation of a novel micromachined microphone. The design of the microphone is based on the well-known two-poly processes. The design as shown in Fig.1 has four merits, (1) rigid-diaphragm formed by the rib-reinforced poly-Si as acoustic wave receiver and moving-electrodes, (2) flexible-spring formed by thin poly-Si as diaphragm supporter, (3) rigid-diaphragm anchored to flexible-spring by central poly-via, and (4) very rigid plate formed by high-aspect-ratio (HARM) trench-refilled poly-Si as stationary-electrodes and back-plate. To demonstrate the feasibility, the two-poly microphone has been implemented and tested. Typical measurement results show that the sensitivity of microphone is 12.63 mV/Pa (−37.97 dB/Pa) measured at the sound level of 94 dB.