• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.5
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• pp.276-283
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• 2017

A polysilicon-based metal-semiconductor-metal (MSM) photodetector was fabricated by means of our new methods. Its photoresponse characteristics were analyzed to see if it could be applied to a sensor system. The processes on which this study focused were an alloy-annealing process to form metal-polysilicon contacts, a post-annealing process for better light absorption of as-deposited polysilicon, and a passivation process for lowering defect density in polysilicon. When the alloy annealing was achieved at about $400^{\circ}C$, metal-polysilicon Schottky contacts sustained a stable potential barrier, decreasing the dark current. For better surface morphology of polysilicon, rapid thermal annealing (RTA) or furnace annealing at around $900^{\circ}C$ was suitable as a post-annealing process, because it supplied polysilicon layers with a smoother surface and a proper grain size for photon absorption. For the passivation of defects in polysilicon, hydrogen-ion implantation was chosen, because it is easy to implant hydrogen into the polysilicon. MSM photodetectors based on the suggested processes showed a higher sensitivity for photocurrent detection and a stable Schottky contact barrier to lower the dark current and are therefore applicable to sensor systems.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.7
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• pp.58-68
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• 1995

Polysilicon capacitors with pyrogenic oxide and TEOX oxide as insulators were fabricated to develop capacitors which can be applied to analog CMOS IC, and the characteristics of the capacitors were compared with each other. The morphology of bottom polysilicon in pyrogenic oxide capacitor is degraded due to the generaged protuberances of the polysilicon grain during oxidataion. The polysilican capacitor with pyrogenic oxide of 57 nm thickness showed that the effective potential barrier height of 0.45 eV is much less than that of MOS capacitor (3.2 eV)when the top electrode is biased with a positive volgate. The morphology of the polysilicon capacitor with TEOS oxide, however, was not degraded during oxide deposition by LPCVD. The polysilicon capacitor with TEOS oxide of 54 nm thickness showed the effective potential barrier height of 1.28 eV when the top electrode is biased with a negative voltage. Therefore, it is concluded that the polysilicon capacitor with TEOS oxide is more applicable to analog CMOS IC than the pyrogenic oxide polysilicon capacitor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.2
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• pp.101-105
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• 1998

This paper describes anisotropic etching technology of highly doped polysilicon. The main etching gases are $Cl_2$ and $SiCl_4$ for reactive ion etching of polysilicon. The mixed $CHCl_3$ to main etching gas makes polymer on etching side wall, so it prevents side etching of polysilicon. The etch rate of polysilicon is increased with increasing RF power. But the etching rate is decreased as the flow rate of $CHCl_3$ is increased with fixed RF power. The etch selectivity of polysilicon and $SiO_2$ is about 12:1. And that of polysilicon and $Si_3N_4$ is about 19:1. In the main etching gas condition, the slope of polysilicon is same as that of photoresist. But in the mixed $CHCl_3$ condition, the slope of polysilicon is larger than that of photoresist. This represents that the polymer made on side wall by added $CHCl_3$ prevents side etching, so anisotropic etching can be possible by polymer.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.143-144
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• 2019

Recently, environmental pollution related to global warming is on the rise. Meanwhile, renewable energy is a representative example of many efforts to develop eco-friendly energy to solve the depletion of natural resources and the depletion of petroleum resources in conjunction with global warming. Among them, photovoltaic power generation is increasing the subsidies for the government to increase the production of photovoltaic electricity of the general public, showing a high growth rate. However, polysilicon, which is a raw material of the photovoltaic panel, generates waste called polysilicon sludge in the manufacturing process. In order to produce 1 ton of polysilicon, about 2 tons of waste polysilicon sludge is generated. In 2012, polysilicon sludge was generated at 78,000 tons, with an average of about 220 tons per day. The sludge generated due to insufficient treatment of polysilicon sludge is currently solidified and is processed by landfilling. Therefore, in this study, polysilicone sludge is used as the concept of admixture, and the physical properties of the matrix according to the polysilicon sludge replacement ratio based on light burned magnesia is determined.

• Korean Journal of Materials Research
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• v.5 no.2
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• pp.203-207
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• 1995

Polysilicon this film transistors (poly-Si TFTs) with different channel dimensions were fabricated on low-temperature crystalized amorphous silicon films and on as-deposited polysilicon films. The electrical characteristics of these TFTs were characterized and compared. The performance of the TFTs fabricated on the solid-phase crystalized amophous silicon films ws showon to be superior to that of the TFTs fabricated on the as-deposited polysilicon films. It was found that the performance of poly-Si TFTs depends strongly on the material characteristics of the polysilicon films used as the active layers, but only weakly on the channel dimensions.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.153-159
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• 1997

A thermally-driven polysilicon microactuator has been fabricated using surface micromachining techniques. It consists of P-doped polysilicon as a structural layer and TEOS(tetraethylorthosilicate) oxide as a sacrificial layer. The polysilicon was annealed for the relaxation of residual stress which is the main cause to its deformation such as bending and buckling. And newly developed HF GPE(gas-phase etching) process was also employed to eliminate the troublesome stiction problem using anhydrous HF gas and CH$_{3}$OH vapor, and successfully fabricated the microactuators. The actuation is incurred by the thermal expansion due to the current flow in the active polysilicon cantilever, which motion is amplified by lever mechanism. The moving distance of polysilicon microactuator was experimentally conformed as large as 21 .mu. m at the input voltage level of 10V and 50Hz square wave. The actuating characteris- tics are also compared with the simulalted results considering heat transfer and thermal expansion in the polysilicon layer. This microactuator technology can be utilized for the fabrication of MEMS (microelectromechanical system) such as microrelay, which requires large displacement or contact force but relatively slow response.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.3
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• pp.208-212
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• 2008

This paper reports physical properties of in situ boron doped silicon films made from boron source gas and silane ($SiH_4$) gas in a conventional low-pressure chemical vapor deposition vertical furnace. If the p-type polysilicon is formed by boron implantation into undoped polysilicon, the plasma nitridation (PN) process is added on the oxide in order to suppress boron penetration that can be caused during the thermal treatments used in fabrication. In-situ boron doped polysilicon deposition can complete p-type polysilicon film with only one deposition process and need not the PN process, because there is not interdiffusion of dopant at the intermediate temperatures of the subsequent steps. Since in-situ boron doped polysilicon films have higher work function than that of n-type polysilicon and they are compatible with the underlying oxide, they may be promising materials for improving memory cell characteristics if we make its profit of these physical properties.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.7
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• pp.56-62
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• 1998

Polysilicon resistors with high thermal stability have been fabricated by a new mixed process using POCl$_{3}$ doping and arsenic implantation. Varous temeprature coefficients, which range form 510 ppm/.deg. C to -302 ppm/.deg. C, were shown from the fabricated polysilicon resistors with sheet resistance of 58~107 .ohm./sq in the operating temeprature of 27~150.deg. C. The temperature coefficient of the polysilicon resistor by the mixed technology was about 4.3 times as low compared to the conventional polysilicon resistor using POCl$_{3}$ doped single process with the same sheet resistance of 75.ohm./sq. In addition, the mixed technology can be applied to obtain nearly zero temperature coefficient for polysilicon resistors which are reliable and insensitive to temperature.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.265-266
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• 2018

In recent years, active loess cement has been used instead of cement in order to reduce the amount of cement and industrial byproducts that are the main cause of environmental pollution. We also used polysilicon sludge as a by-product to reduce the amount of cement used and to improve the environmental pollution due to the reduction of carbon dioxide. Polysilicon is a raw material used in the production of panels for solar power generation. When producing 1 ton of polysilicon, 2 tons of sludge is generated. It is an experiment to reduce sludge treatment and cement usage. This study analyzed basic characteristics of polysilicon sludge and active loess cement according to replacment ratio.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.165-166
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• 2018

Researches for the development of renewable energy as a fuel substitute for global warming and depletion of petroleum resources are actively being carried out. Among them, the annual growth rate of PV generation is 20.73%, which is higher than other renewable energy sources. However, the production of 1 ton of polysilicon, which is known as a raw material for solar power generation panels, generates 2 tons of waste. As the demand for PV panels increases, the problem of the treatment of polysilicon sludge is attracting attention, and studies on the utilization of polysilicon sludge are needed. Therefore, in this study, the applicability of polysilicon sludge treated as industrial waste to the lightweight panel for architectural purposes was examined.