• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.44.1-44
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• 2003

• Proceedings of the Korean Vacuum Society Conference
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• 2002.02a
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• pp.93-93
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• 2002

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.7
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• pp.11-16
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• 2016

Silicon carbide (SiC) has received significant attention over the past decade because of its high-voltage, high-frequency and high-thermal reliability in devices compared to silicon. Especially, a SiC Schottky barrier diode (SBD) is most often used in low-voltage switching and low on-resistance power applications. However, electric field crowding at the contact edge of SBDs induces early breakdown and limits their performance. To overcome this problem, several edge termination techniques have been proposed. This paper proposes an improvement in the breakdown voltage using a double-field-plate structure in SiC SBDs, and we design, simulate, fabricate, and characterize the proposed structure. The measurement results of the proposed structure, demonstrate that the breakdown voltage can be improved by 38% while maintaining its forward characteristics without any change in the size of the anode contact junction region.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.640-645
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• 2010

This paper describes the power generating property of hydrothermally grown ZnO nanorods on a flexible polyethersulfone (PES) substrate. The piezoelectric currents generated by the ZnO nanorods were measured when bending the ZnO nanorod by using I-AFM, and the measured piezoelectric currents ranged from 60 to 100 pA. When the PtIr coated tip bends a ZnO nanorod, piezoelectrical asymmetric potential is created on the nanorod surface. The Schottky barrier at the ZnO-metal interface accumulates elecntrons and then release very quickly generating the currents when the tip moves from tensile to compressed part of ZnO nanorod. These ZnO nanorods were grown almost vertically with the length of 300-500 nm and the diameter of 30-60 nm on the Ag/Ti/PES substrate at $90^{\circ}C$ for 6 hours by hydrothermal method. The metal-semiconductor interface property was evaluated by using a HP 4145B Semiconductor Parameter Analyzer and the piezoelectric effect of the ZnO nanorods were evaluated by using an I-AFM. From the measured I-V characteristics, it was observed that ZnO-Ag and ZnO-Au metal-semiconductor interfaces showed an ohmic and a Schottky contact characteristics, respectively. ANSYS finite element simulation was performed in order to understand the power generation mechanism of the ZnO nanorods under applied external stress theoretically.

• Journal of Sensor Science and Technology
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• v.16 no.4
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• pp.259-262
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• 2007

This paper describes the electrical characteristics of polycrystalline (poly) 3C-SiC thin film diodes, in which poly 3C-SiC thin films on n-type and p-type Si wafers, respectively, were deposited by APCVD using HMDS, $H_{2}$, and Ar gas at $1150^{\circ}C$ for 3 hr. The schottky diode with Au/poly 3C-SiC/Si (n-type) structure was fabricated. Its threshold voltage ($V_{bi}$), breakdown voltage, thickness of depletion layer, and doping concentration ($N_{D}$) value were measured as 0.84 V, over 140 V, 61 nm, and $2.7{\times}10^{19}cm^{-3}$, respectively. Moreover, for the good ohmic contact, Al/poly 3C-SiC/Si (n-type) structure was annealed at 300, 400, and $500^{\circ}C$, respectively for 30 min under the vacuum condition of $5.0{\times}10^{-6}$ Torr. Finally, the p-n junction diodes fabricated on the poly 3C-Si/Si (p-type) were obtained like characteristics of single 3CSiC p-n junction diode. Therefore, poly 3C-SiC thin film diodes will be suitable for microsensors in conjunction with Si fabrication technology.

• Industry Promotion Research
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• v.3 no.1
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• pp.1-5
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• 2018

$SnO_2$ films were annealed in a vaccum atmosphere conditions to research the temperature dependency of current-voltage characteristics in according to the bonding structures. The $SnO_2$ film annealed in a vacuum became an amorphous structure but films annealed in an atmosphere condition had a crystal structure. The defects or depletion layer were formed by the electron-hole combination after annealing processes, and the electrical properties were changed depending on the crystal structure, binding energy and the variation of carriers. $SnO_2$ became more crystal-structural with increasing the annealing temperature, and the current increased at $SnO_2$ film annealed at $150^{\circ}C$ with Schottky current.

• Industry Promotion Research
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• v.1 no.2
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• pp.13-17
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• 2016

ZTO films were annealed in a vaccum atmosphere conditions to research the temperature dependency of current-voltage characteristics. The ZTO film annealed in a vacuum became an amorphous structure but films annealed in an atmosphere condition had a crystal structure. The defects or depletion layer were formed by the electron-hole combination after annealing processes, and the electrical properties were changed depending on the crystal structure, binding energy and the variation of carriers. ZTO became more crystal-structural with increasing the annealing temperature, and the current increased at ZTO film annealed at $150^{\circ}C$ with Schottky contact.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.2
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• pp.179-184
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• 2016

In recent years, the on-resistance, power loss and cell density of Si power devices have not exhibited significant improvements, and performance is approaching the material limits. GaN is considered an attractive material for future high-power applications because of the wide band-gap, large breakdown field, high electron mobility, high switching speed and low on-resistance. Here we report on the Ohmic contact resistance and reverse-bias characteristics of AlGaN/GaN Schottky barrier diodes with and without annealing. Annealing in oxygen at $500^{\circ}C$ resulted in an increase in the breakdown voltage from 641 to 1,172 V for devices with an anode-cathode separation of $20{\mu}m$. However, these annealing conditions also resulted in an increase in the contact resistance of $0.183{\Omega}-mm$, which is attributed to oxidation of the metal contacts. Auger electron spectroscopy revealed diffusion of oxygen and Au into the AlGaN and GaN layers following annealing. The improved reverse-bias characteristics following annealing in oxygen are attributed to passivation of dangling bonds and plasma damage due to interactions between oxygen and GaN/AlGaN. Thermal annealing is therefore useful during the fabrication of high-voltage GaN devices, but the effects on the Ohmic contact resistance should be considered.

• Journal of Korea Multimedia Society
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• v.3 no.5
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• pp.535-541
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• 2000

In this paper, we analyzed the characteristics of schottky junction to develop the voltage swing of ISL, and simulated the characteristics with the programs at this junctions. Simulation programs for analytic characteristics are the SUPREM V, SPICE, Medichi, Matlab. The schottky junction is rectifier contact between platinum silicide and silicon, the characteristics with programs has simulated the same conditions. The analytic parameters were the turn-on voltage, saturation current, ideality factor in forward bias, and has shown the results of breakdown voltage between actual characteristics and simulation characteristics in reverse bias. As a result, th forward turn-on voltage, reverse breakdown voltage, barrier height were decreased but saturation current and ideality factor were increased by substrates increased concentration variations.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.10
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• pp.877-882
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• 2005

In order to fabricate a high breakdown SiC-SBD (Schottky barrier diode), we investigate an effect on metal guard ring (MGR) in breakdown characteristics of the SiC-SBD. The breakdown characteristics of MGR-type SiC-SBD is significantly dependent on both the guard ring metal and the alloying time of guard ring metal. The breakdown characteristics of MGR-type SiC-SBDs are essentially improved as the alloying time of guard ring metal is increased. The SiC-SBD without MGR shows less than 200 V breakdown voltage, while the SiC-SBD with Al MGR shows approximately 700 V breakdown voltage. The improvement in breakdown characteristics is attributed to the field edge termination effect by the MGR, which is similar to an implanted guard ring-type SiC-SBD. There are two breakdown origins in the MGR-type SiC-SBD. One is due to a crystal defects, such as micropipes and stacking faults, in the Epi-layers and the SiC substrate, and occurs at a lower electric field. The other is due to the destruction of guard ring metal, which occurs at a higher electric field. The demolition of guard ring metal is due to the electric field concentration at an edge of Schottky contact metal.