• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.274-277
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• 1991

A piezoresistive silicon resonator which can be used as an accelerometer is designed and fabricated using silicon micromachining techniques. The device consists of a seismic mass and four deflection beams in which eight piezoresistors are diffused. The structure is fabricated by EPW etching process. The piezoresistors are properly arranged and connected to make a bridge circuit, with which acceleration in only one direction can be measured. According to the experimental results, the first resonant frequency of this resonator is above 15 kHz, and this transducer has a sensitivity of 5.56 ${\mu}V/Vg$.

• Journal of Sensor Science and Technology
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• v.15 no.3
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• pp.164-167
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• 2006

Calorimeter is one of widely used biosensors. Conventional or existing calorimeters are realized directly on a silicon wafer which has very high thermal conductivity. It results in decreasing temperature difference between junctions and it makes a sensitivity of calorimeter to be decreased. In this study, the microcalorimeter was made by using MEMS(Micro Electro Mechanical Systems)-technology and hot junctions of the microcalorimeter are released from a silicon substrate to reduce loss of generated heat by reactions between biomolecules. Sensitivity of the released microcalorimeter was 18 mV/M which is 1.5 times higher than another calorimeters on silicon substrate by reactions between biotin and streptavidin.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.210-212
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• 1993

In this paper, a silicon microvalve has been fabricated using micromachining technology. The valve consists of the several thin silicon diaphragms which are designed to open and close depending on the pressure difference. It is supposed to pass fluids in only one direction. The thin diaphragms are fabricated by boron etch stop using an anisotropic etchant, EPW. The fabricated valve has been tested for various pneumatic pressure. According to the experimental results, the slit width of the valve increases as the pneumatic pressure increases.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.7
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• pp.30-36
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• 1997

Bump bonded piezoesistive silicon accelerometer was fabricated by the porous silicon micromachining and th eprocess technique of integrated circuit. The output voltage of the accelerometer fabricated on (111)-oreiented Si substrates with n/n$^{+}$n triple layers showed good linear characteristic of less than 1%. The measured sensitivity and the resonant frequency was about 743 .mu.V/g and 2.04 kHz, respectively. And the transverse sensitivity of 5.2% was measured from the accelerometer. Also, to investigate an influence on the output characteristics of the sensor due to bump bonding, the values of the piezoresistors were measured through thermal-cycling test in the temperature variation form -50 to 120.deg. C. Then, there was 0.014% resistance changes about 3.61 k.ohm., so sthe output charcteristics of the sensor was less affected by bump bonding.g.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1985-1987
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• 2002

Silicon bulk micromachined micromirrors are designed and fabricated for out-of-plane right angle reflection. The micromirror is comprised of a minor plate, springs, magnetic bars and electrodes. Single crystalline silicon is used for a flatness improvement of a mirror plate. Out-of-plane right angle reflection requires a 45 degree operation of the micromirror. The micromirrors are operated by applying a magnetic field, which is generated by a coil located below a substrate. For an individual mirror operation, each mirror is clamped using an electrostatic force against the electromagnetic force. Angular deflections are measured and compared with theoretical data. The micro mirror operates up to 45 degree when magnetic field is 4 kA/m which is generated by a 115 mA coil current Simple addressing is tested, and it is shown that a clamping voltage is less than 5V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.411-414
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• 1998

In this paper, the silicon-nitride membrane structure for IR sensor was fabricated through the etching and the direct bonding. The PT layer as a IR detection layer was deposited on the membrane and its characteristics were measured. The attack of PT layer during the etching of silicon wafer as well as the thermal isolation of the IR detection layer can be solved through the method of bonding/etching of silicon wafer. Because the PT layer of c-axial orientation rained thermal polarization without polling, the more integration capability can be achieved. The surface roughness of the membrane was measured by AFM, the micro voids and the non-contacted area were inspected by IR detector, and the bonding interface was observed by SEM. The polarization characteristics and the dielectric characteristics of the PT layer were measured, too.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.815-819
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• 1998

The silicon-nirtide membrane structure for IR sensor was fabricated through the etching and the direct bonding. The PRO($PbTiO_3$ ) layer for a IR detection was coated on the membrane and its characteristics were measured. The a attack of PTO layer during the etching of silicon wafer as well as the thermal isolation of the IR detection layer were eliminated through the method of bonding/etching of silicon wafer. The surface roughness of the membrane was measured by AFM, the micro voids and the non-contacted area were inspected by the PTO layer were measured, too.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.481-485
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• 1987

The fabrication of a micro mass flow sensor on a silicon chip by means of micro-machining technology is described on this paper. The operation of micro mass flow sensor is based on the heat transfer from a heated chip to a fluid. The temperature differences on the chip is a measure for the flow velocity in a plane parallel with the chip surface. An anisotropic etching technigue was used for the formation of the V-type groove in this fabrication. The micro mass flow sensor is made up of two main parts ; A thin glass plate embodying the connecting parts and mass flow sensor parts in silicon chip. This sensor have a very small size and a neglible dead space. Micro mass flow sensor can fabricate on silicon chip by micro machining technology too.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2395-2397
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• 2005

A low voltage operated piezoelectric RF MEMS in-line switch has been realized by using silicon bulk micromachining technologies for advanced mobile/wireless applications. The developed RF MEMS in-line switches were comprised of four piezoelectric cantilever actuators with an Au contact metal electrode and a suspended Au signal transmission line above the silicon substrate. The measured operation dc bias voltages were ranged from 2.5 to 4 volts by varying the thickness and the length of the piezoelectric cantilever actuators, which are well agreed with the simulation results. The measured isolation and insertion loss of the switch with series configuration were -43dB and -0.21dB (including parasitic effects of the silicon substrate) at a frequency of 2GHz and an actuation voltage of 3 volts.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.246-250
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• 2003

In this study, two new types of micro-grippers in which micro-fingers are actuated by piezoelectric multi-layer benders and stacks are introduced for the manipulation of micrometer-sized objects. First, we constructed a 3-chopstick-mechanism tungsten gripper, which is composed of three chopsticks: two are designed to grip micro-objects, and tile third is used to help grasp and release the objects through overcoming especially electrostatic force among some surface effects including electrostatic, van der Waals forces and surface tension. Second, a 2-chopstick-mechanism silicon micro-gripper that uses an integrated force sensor to control the gripping force was developed. The micro-gripper is composed of a piezoelectric multilayer bender for actuating the gripper fingers, silicon fingertips fabricated by use of silicon-based micromachining, and supplementary supports. The micro-gripper is referred to as a hybrid-type micro-gripper because it is composed of two main components; micro-fingertips fabricated using micromachining technology to integrate a very sensitive force sensor for measuring the gripping force, and piezoelectric gripper finger actuators that are capable of large gripping forces and moving strokes. The gripping force signal was found to have a sensitivity of 667 N/V. To the design of each of components of both of the grippers. a systematic design approach was applied, which made it possible to establish the functional requirements and design parameters of the micro-grippers. The micro-grippers were installed on a manual manipulator to assess its performance in tasks such as moving micro-objects from one position to a desired position. The experiment showed that the micro-grippers function effectively.