• Journal of Electrical Engineering and information Science
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• v.2 no.3
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• pp.132-138
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• 1997

Electrical characteristics of split-gate flash EEPROM with triple polysilicon is investigated in terms of effects of floating gate and offset gate. In order to search for t the effects of offset gate on programming characteristics, threshold voltage and drain current are studied with variation of control gate voltage. The programming process is believed to depend on vertical and horizontal electric field as well as offset gate length. The erase and program threshold voltage are found to be almost constant with variation of control gate voltage above 12V, while endurance test indicates degradation of program threshold voltage. With increase of offset gate length, program threshold voltage becomes smaller and the drain source voltage just after program under constant control gate voltage becomes higher.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.2
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• pp.83-88
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• 1999

Series connection of power semiconductor devices is selected in high voltage and high power applications. It is important to prevent the overvoltage from being induced across a device above ratings by the proper voltage balancing in the field of IGBT series connection. In addition, the overvoltage induced by a stray inductance has to be limited in the high power circuit. This paper proposes a new gate control scheme which can balance the voltage properly and limit the overshoot by controlling the slope of collector voltage under the turn-off transient in the series connected IGBTs. The proposed gate control scheme changes the slope of collector voltage by sensing the collector voltage and controlling the gate signal actively. The new series connected IGBT gate driver is made and its validity is verified by the experimental results for series connected IGBT circuit.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.195-197
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• 1998

The large scale industry needs high voltage converters. Therefore series connection of power semiconductor devices is necessary. It is important to prevent a device induced the overvoltage above ratings by proper voltage balancing in the field of IGBT series connection. In addition, the overvoltage induced by a stray inductance has to be limited in the high power circuit. This paper proposes a new gate control scheme which can balance the voltage properly and limit the overshoot by control the slope of collector voltage under series connected IGBT turn-off transient. The propose gate control scheme limits the overvoltage by sensing the collector voltage and controlling the gate signal actively. The new series connected IGBT gate driver is made and its validity is verified by the experimental results for series connected IGBT circuit.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.1
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• pp.99-104
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• 1999

The large scale industry needs high voltage converters. Therefore series connection of power semiconductor devices is necessary. It is important to prevent the overvoltage from being induced across a device above ratings by the proper voltage balancing in the field of IGBT series connection. In addition, the overvoltage induced by a stray inductance has to be limited in the high power circuit. This paper proposes a new gate control scheme which can balance the voltage properly and limit the overshoot by controlling the slope of collector voltage under the turn-off transient in the series connected IGBTs. The proposed gate control scheme which senses the collector voltage and controls the gate signal actively limits the overvoltage. The new series connected IGBT gate driver is made and its validity is verified by the experimental results in the series connected IGBT circuit.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.10
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• pp.720-725
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• 2013

Power MOSFET operate voltage-driven devices, design to control the large power switching device for power supply, converter, motor control, etc. We have analyzed trench process, field limit ring process for fabrication of unified trench gate power MOSFET. And we have analyzed electrical characteristics of fabricated unified trench gate power MOSFET. The optimal trench process was based on SF6. After we carried out SEM measurement, we obtained superior trench gate and field limit ring process. And we compared electrical characteristics of planar and trench gate unified power MOSFET after completing device fabrication. As a result, the both of them was obtained 500 V breakdown voltage. However trench gate unified power MOSFET was shown improved Vth and on state voltage drop characteristics than planar gate unified power MOSFET.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.10
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• pp.713-719
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• 2013

Power MOSFET operate voltage-driven devices, design to control the large power switching device for power supply, converter, motor control, etc. We have optimal designed planar and trench gate power MOSFET for high breakdown voltage and low on resistance. When we have designed $6,580{\mu}m{\times}5,680{\mu}m$ of chip size and 20 A current, on resistance of trench gate power MOSFET was low than planar gate power MOSFET. The on state voltage of trench gate power MOSFET was improved from 4.35 V to 3.7 V. At the same time, we have designed unified field limit ring for trench gate power MOFET. It is Junction Termination Edge type. As a result, we have obtained chip shrink effect and low on resistance because conventional field limit ring was convert to unify.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.202-209
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• 2000

This paper introduces the main function and protection method of IGBT gate driver that designed by KOROS. Recently, the applications of insulated gate bipolar transistors(IGBTs) have expanded widely, particularly in the area of railway converters. This driver is suitable for railway traction applications, so they are designed for circumstance of railway vehicle such as vibration. The input control power for this driver is supplied from battery charger of railway. it is no necessary an isolated power supply board or auxiliary power supply, with substantial savings in cost and space in railway applications. This gate driver can be used wide range of input voltage. So, performance of the driver has no relation with the battery voltage(70V∼110V). The protection methods of IGBT gate driver have many kind of ways, but this gate driver it designed to apply to converter for railway system, so this gate driver includes protection for arm short current and low control power voltage, etc. And the process of protection method and protection reference value are optimized by means of sufficient test with our own facilities.

• Journal of Information Display
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• v.7 no.3
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• pp.27-30
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• 2006

This paper presents a comprehensive study on threshold voltage $(V_{th})$ control of organic thin-film transistors (OTFTs) with dual-gate structure. The fabrication of dual-gate pentacene OTFTs using plasma-enhanced atomic layer deposited (PEALD) 150 nm thick $Al_{2}O_{3}$ as a bottom gate dielectric and 300 nm thick parylene or PEALD 200 nm thick $Al_{2}O_{3}$ as both a top gate dielectric and a passivation layer was investigated. The $V_{th}$ of OTFT with 300 nm thick parylene as a top gate dielectric was changed from 4.7 V to 1.3 V and that with PEALD 200 nm thick $Al_{2}O_{3}$ as a top gate dielectric was changed from 1.95 V to -9.8 V when the voltage bias of top gate electrode was changed from -10 V to 10 V. The change of $V_{th}$ of OTFT with dual-gate structure was successfully investigated by an analysis of electrostatic potential.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.5
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• pp.361-365
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• 2019

Although there is no strict definition of a power semiconductor device, a general description is a semiconductor that has capability to control more than 1 W of electricity. Integrated gate bipolar transistors (IGBTs), which are power semiconductors, are widely used in voltage ranges above 300 V and are especially popular in high-efficiency, high-speed power systems. In this paper, the size of the gate was adjusted to test the variation in the yield voltage characteristics by measuring the electric field concentration under the trench gate. After the experiment Synopsys' TCAD was used to analyze the efficiency of threshold voltage, on-state voltage drop, and breakdown voltage by measuring the P- region and its size under the gate.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.3
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• pp.195-203
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• 2005

Recently, a novel multi-bit nonvolatile memory based on double gate (DG) MOSFET is proposed to overcome the short channel effects and to increase the memory density. We need more complex voltage schemes for DG MOSFET devices. In view of peripheral circuits driving memory cells, one should consider various voltage sources used for several operations. It is one of the key issues to minimize the number of voltage sources. This criterion needs more caution in considering a DG nonvolatile memory cell that inevitably requires more number of events for voltage sources. Therefore figuring out the permissible range of operating bias should be preceded for reliable operation. We found that reliable operation largely depends on the depletion conditions of the silicon channel according to charge amount stored in the floating gates and the negative control gate voltages applied for read operation. We used Silvaco Atlas, a 2D numerical simulation tool as the device simulator.