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In this paper, high performance read-out integrated circuits (ROIC) for infrared (IR) image sensor applications is proposed. Because an uncooled microbolometer image sensor, used in an IR image sensor, is made by a micro electro mechanical systems process, the resistance of bolometer by each process does not appear same value under same temperature condition. This resistance variation generates a different output signal for same input by each chip. In order to improve on these drawbacks, a ROIC, which compensates for the error described above, was designed. Instead of a single input mode, a differential input mode ROIC was proposed and thus, a new circuit structure was proposed. Using results from a computer simulation, improvements such as that the effect of the process error was decreased 10---12% without an additional compensation circuit was found. Based on the simulation results, a prototype device including a ROIC and a micro bolometer with 16 × 16 cell arrays was fabricated and characterized.

An uncooled microbolometer image sensor, used in an IR image sensor, is made by a micro electro mechanical systems (MEMS) process, so the value of the microbolometer resistor has a process variation. Also, the reference resistor, which is used to connect to the microbolometer, is fabricated by a standard CMOS process, and the difference between the values of the microbolometer resistor and the reference resistor generates an unwanted output signal for the same input from the sensor array. In order to minimize this problem, a new CMOS read-out integrated circuit (ROIC) was designed. Instead of a single input mode, a differential input mode scheme and a simple method to compensate the resistor value are proposed. Using results from a computer simulation, it is observed that the output characteristic of the ROIC was improved and the effect of the process variation was decreased without using complex compensation circuits. Based on the simulation results, a prototype device including an ROIC that was fabricated by a standard 0.25um CMOS process and a microbolometer with a 16 x 16 sensor array was fabricated and characterized.

To construct the accurate radio satellite navigation system, the efficient communication each satellite with the ground station is very important. Throughout the communication, the orbit of each satellite can be corrected, and those information will be used to analyze the satellite satus by the operator. Since there are limited resources of ground station, the schedule of antenna`s azimuth and elevation angle should be optimized. On the other hand, the satellite in the medium earth orbit does not pass the same point of the earth surface due to the rotation of the earth. Therefore, the antenna pass schedule must be updated at the proper moment. In this study, Q learning approach which is a form of model-free reinforcement learning and genetic algorithm are considered to find the optimal antenna schedule. To verify the optimality of the solution, numerical simulations are conducted.

In this paper, we propose and discuss the design using a simple method that reduces the fixed pattern noise(FPN) generated on the amorphous Si() bolometer. This method is applicable to an IR image sensor. This method can also minimize the size of the reference resistor in the readout integrated circuit(ROIC) which processes the signal of an IR image sensor. By connecting four bolometer cells in parallel and averaging the resistances of the bolometer cells, the fixed pattern noise generated in the bolometer cell due to process variations is remarkably reduced. Moreover an bolometer cell, which is made by a MEMS process, has a large resistance value to guarantee an accurate resistance value. This makes the reference resistor be large. In the proposed cell structure, because the bolometer cells connected in parallel have a quarter of the original bolometer`s resistance, a reference resistor, which is made by poly-Si in a CMOS process chip, is implemented to be the size of a quarter. We designed a ROIC with the proposed cell structure and implemented the circuit using a 0.35 um CMOS process.

In this paper, effects of the trench angle() on the breakdown voltage according to the process parameters of p-base region and doping concentrations of n-drift region in a Trench Gate IGBT (TIGBT) device were analyzed by computer simulation. Processes parameters used by variables are diffusion temperature, implant dose of p-base region and doping concentration of n-drift region, and aspects of breakdown voltage change with change of each parameter were examined. As diffusion temperature of the p-base region increases, depth of the p-base region increases and effect of the diffusion temperature on the breakdown voltage is very low in the case of small trench angle() but that is increases 134.8 % in the case of high trench angle(). Moreover, as implant dose of the p-base region increases, doping concentration of the p-base region increases and effect of the implant dose on the breakdown voltage is very low in the case of small trench angle() but that is increases 232.1 % in the case of high trench angle(). These phenomenons is why electric field concentrated in the trench is distributed to the p-base region as the diffusion temperature and implant dose of the p-base increase. However, effect of the doping concentration variation in the n-drift region on the breakdown voltage varies just 9.3 % as trench angle increases from to . This is why magnitude of electric field concentrated in the trench changes, but direction of that doesn`t change. In this paper, respective reasons were analyzed through the electric field concentration analysis by computer simulation.

Achieving excellent reliability for imprint patterns molded by stamps for the industrial application of nanoimprint lithography (NIL) is an important challenge. Usually, defects are produced by incomplete filling of negative patterns and the shrinkage phenomenon of polymers in conventional NIL. In our research, we investigated patterns that undergo varied temperature or varied pressure periods during thermal NIL with the goal of resolving issues dealing with the shrinkage and defective filling of polymers. The effects on the formation of polymer patterns in several profiles of imprint processes were also studied. Consequently, we observed that more precise patterns were formed with varied temperature (VT)-NIL and varied pressure (VP)-NIL. NIL has a free space compensation effect on the polymers in the stamp cavities. From the results of the experiments, the polymer's filling capability was improved. The VT-NIL was merged with the VP-NIL for a better filling property. The patterns imprinted using the merged NIL were compared with the results of the conventional NIL. In this study, an improvement in reliability from the results of thermal NIL was achieved.

We propose a high performance ROIC for IR image sensor applications. Because a micro bolometer image sensor, used in an IR image sensor, is made by a MEMS process, the resistance of bolometers by each process does not appear same value under same IR energy incident condition. This resistance variation generates a different output signal for same input by each chip. Instead of a single input mode, we used a differential input mode to the proposed ROIC and thus, a new circuit structure that has high immunity to the process variations of micro bolometer was invented. This result is due to the characteristics of the differential input mode that suppress the commonly appeared error and amplify the differentially applied signal. Using results from a computer simulation, improvement such as that the effect of the process error on the bolometer's resistance was decreased 10 ~ 12% without an additional compensation circuit was found. Moreover we had analyzed the results by numerical methods and found that it is possible to control the gain and compensation ability by design the capacitors of the integrator appropriately. A full chip including a ROIC and a micro bolometer with 16 X 16 cell arrays was designed and implemented in standard 0.25um CMOS process.

A trench gate insulated gate bipolar transistor(IGBT) employing a shielding layer, which improves the breakdown voltage characteristic is proposed and verified by 2D numerical simulation. The shielding layer concept is proposed to alleviate the electric field of concentrated on the trench bottom corner. By simulation results, we verified that a shielding layer reduced the electric fields not only in the gate oxide but in the p-base region. Compared with conventional trench gate IGBT, about 33% increment of forward breakdown voltages are achieved.

In this paper we introduced the shielding layer concept in order to alleviate the electric field of concentrated on the trench bottom corner. The shielded trench gate IGBT is a trench gate IGBT with a P+ shielding layer bottom of a trench gate. By simulation results, we verified that a shielding layer reduced the electric fields not only in the gate oxide but in the p-base region. Compared with conventional trench gate IGBT, about 33% increment of forward breakdown voltages are achieved.

As infrared light is radiated, the CMOS Readout IC (ROIC) for the microbolometer type infrared sensor detects voltage or current when the resistance value in the bolometer sensor varies. One of the serious problems in designing the ROIC is that resistances in the bolometer and replica resistor have process variation. This means that each pixel does not have the same resistance, causing serious fixed pattern noise problems in sensor operations. In this paper, differential input stage readout architecture is suggested for bias offset reduction, noise immunity and high sensing margin. In addition, using this scheme the effects of a process variation problem and various other bias heating noise problems, are reduced. In this paper, a prototype ROICs, intended for uncooled microbolometer infrared focal plane array, is designed and fabricated. The proposed architecture is demonstrated by fabrication of a prototype consisting of 32 x 32 pixels fabricated in a 0.25-μm CMOS process.

As infrared light is radiated, the CMOS readout IC (ROIC) for the microbolometer type infrared sensor detects voltage or current when the resistance value in the bolometer sensor varies. One of the serious problems in designing the ROIC is that resistances in the bolometer and replica resistor have process variation. This means that each pixel does not have the same resistance, causing serious fixed pattern noise problems in sensor operations. In this paper, differential input stage readout architecture is suggested for bias offset reduction, noise immunity and high sensing margin. In addition, using this scheme the effects of a process variation problem and various other bias heating noise problems, are reduced. In this paper, a prototype ROICs, intended for uncooled microbolometer infrared focal plane array, is designed and fabricated. The proposed architecture is demonstrated by fabrication of a prototype consisting of 32 times 32 pixels fabricated in a 0.25-mum CMOS process