• Journal of the Semiconductor & Display Technology
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• v.21 no.4
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• pp.138-143
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• 2022

We analyzed the influence of post-annealing on Ga₂O₃/n-type 4H-SiC heterojunction diode. Gallium oxide (Ga₂O₃) thin films were deposited by radio frequency (RF) sputtering. Post-deposition annealing at 950℃ in an Oxygen atmosphere was performed. The material properties of Ga₂O₃ and the electrical properties of the diodes were investigated. Atomic Force Microscopy (AFM), X-Ray Diffraction and Scanning Electron Microscope (SEM) images show a significant increase in the roughness and crystallinity of the O₂-annealed films. After Oxygen annealing X-ray Photoelectron Spectroscopy (XPS) shows that the atomic ratio of oxygen increases which is related to a decrease in oxygen vacancy within the Ga₂O₃ film. The O₂-annealed diodes exhibited higher on-current and lower leakage current. Moreover, the ideality factor, barrier height, and thermal activation energy were derived from the current-voltage curve by increasing the temperature from 298 - 434K.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.08a
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• pp.63-66
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• 2003

To diffuse Zn at solid-state, the $SiO-2$/ZnO/$SiO_2$ wafers was made by PECVD and RF Sputter. Thicknesses of bottom $SiO_2$ and cap $SiO_2$ was about 500 ${\AA}$ and about 3500 ${\AA}$. Diffusion temperatures were $760^{\circ}C$, $780^{\circ}C$, and $800^{circ}C$, and diffusion times were 1, 2, 3, 4, 5, and 6 hr. LED chips were fabricated by the diffused wafers at Fab. The peak wavelength of all chips showed about 625~650 nm and red color. Main reason for Iv change was by diffusion temperature not diffusion time. The lower temperature was the higher Iv. We thick that these properties is because of the very high diffusion temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.2
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• pp.155-160
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• 2020

Ga₂O₃/n-type 4H-SiC heterojunction diodes were fabricated by RF magnetron sputtering. The optical properties of Ga₂O₃ and electrical properties of diodes were investigated. I-V characteristics were compared with simulation data from the Atlas software. The band gap of Ga₂O₃ was changed from 5.01 eV to 4.88 eV through oxygen annealing. The doping concentration of Ga₂O₃ was extracted from C-V characteristics. The annealed oxygen exhibited twice higher doping concentration. The annealed diodes showed improved turn-on voltage (0.99 V) and lower leakage current (3 pA). Furthermore, the oxygen-annealed diodes exhibited a temperature cross-point when temperature increased, and its ideality factor was lower than that of as-grown diodes.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.322-322
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• 2010

For boron doping on n-type silicon wafer, around $1,000^{\circ}C$ doping temperature is required, because of the relatively low solubility of boron in a crystalline silicon comparing to the phosphorus case. Boron doping by fiber laser annealing and lamp furnace heat treatment were carried out for the uniformly deposited p-a-Si:H layer. Since the uniformly deposited p-a-Si:H layer by cluster is highly needed to be doped with high temperature heat treatment. Amorphous silicon layer absorption range for fiber laser did not match well to be directly annealed. To improve the annealing effect, we introduce additional lamp furnace heat treatment. For p-a-Si:H layer with the ratio of $SiH_4:B_2H_6:H_2$=30:30:120, at $200^{\circ}C$, 50 W power, 0.2 Torr for 30 min. $20\;mm\;{\times}\;20\;mm$ size fiber laser cut wafers were activated by Q-switched fiber laser (1,064 nm) with different sets of power levels and periods, and for the lamp furnace annealing, $980^{\circ}C$ for 30 min heat treatment were implemented. To make the sheet resistance expectable and uniform as important processes for the $p^+$ layer on a polished n-type silicon wafer of (100) plane, the Q-switched fiber laser used. In consequence of comparing the results of lifetime measurement and sheet resistance relation, the fiber laser treatment showed the trade-offs between the lifetime and the sheet resistance as $100\;{\omega}/sq.$ and $11.8\;{\mu}s$ vs. $17\;{\omega}/sq.$ and $8.2\;{\mu}s$. Diode level device was made to confirm the electrical properties of these experimental results by measuring C-V(-F), I-V(-T) characteristics. Uniform and expectable boron heavy doped layers by fiber laser and lamp furnace are not only basic and essential conditions for the n-type crystalline silicon solar cell fabrication processes, but also the controllable doping concentration and depth can be established according to the deposition conditions of layers.

• Journal of Sensor Science and Technology
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• v.23 no.3
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• pp.185-191
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• 2014

The width of depletion region in a varactor diode can be modulated by varying a reverse bias voltage. Thus, the preferred characteristics of depletion capacitance can obtained by the change in the width of depletion region so that it can select only the desirable frequencies. In this paper, the TV tuner varactor diode fabricated by hyper-abrupt profile control technique is presented. This diode can be operated within 3.3 V of driving voltage with capability of UHF band tuning. To form the hyperabrupt profile, firstly, p+ high concentration shallow junction with $0.2{\mu}m$ of junction depth and $1E+20ions/cm^3$ of surface concentration was formed using $BF_2$ implantation source. Simulation results optimized important factors such as epitaxial thickness and dose quality, diffusion time of n+ layer. To form steep hyper-abrupt profile, Formed n+ profile implanted the $PH_3$ source at Si(100) n-type epitaxial layer that has resistivity of $1.4{\Omega}cm$ and thickness of $2.4{\mu}m$ using p+ high concentration Shallow junction. Aluminum containing to 1% of Si was used as a electrode metal. Area of electrode was $30,200{\mu}m^2$. The C-V and Q-V electric characteristics were investigated by using impedance Analyzer (HP4291B). By controlling of concentration profile by n+ dosage at p+ high concentration shallow junction, the device with maximum $L_F$ at -1.5 V and 21.5~3.47 pF at 0.3~3.3 V was fabricated. We got the appropriate device in driving voltage 3.3 V having hyper-abrupt junction that profile order (m factor) is about -3/2. The deviation of capacitance by hyper-abrupt junction with C0.3 V of initial capacitance is due to the deviation of thermal process, ion implantation and diffusion. The deviation of initial capacitance at 0.3 V can be reduced by control of thermal process tolerance using RTP on wafer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.172-173
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• 2006

Metal-ferroelectric-insulator-semiconductor (MFIS) structures with $Bi_{3.35}La_{0.75}Ti_3O_{12}$ (BLT) ferroelectric film and Zirconium oxide ($ZrO_2$) layer were fabricated on p-type Si(100). $ZrO_2$ and BLT films were prepared by sol-gel technique. Surface morphologies of $ZrO_2$ and BLT film were measured by atomic force microscope (AFM). The electrical characteristics of Au/$ZrO_2$/Si and Au/BLT/$ZrO_2$/Si film were investigated by C-V and I-V measurements. No hysteretic characteristics was observed in the C-V curve of the Au/$ZrO_2$/Si structure. The memory window width m C-V curve of the Au/BLT/$ZrO_2$/Si diode was about 1.3 V for a voltage sweep of ${\pm}5$ V. The leakage current of Au/$ZrO_2$/Si and Au/BLT/$ZrO_2$/Si structures were about $3{\times}10^{-8}$ A at 30 MV/cm and $3{\times}10^{-8}$ A at 3 MV/cm, respectively.

• ETRI Journal
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• v.27 no.5
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• pp.545-550
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• 2005

We have carried out the fabrications of a barrier layer on a polyethersulfon (PES) film and organic light emitting diode (OLED) based on a plastic substrate by means of atomic layer deposition (ALD). Simultaneous deposition of 30 nm $AlO_x$ film on both sides of the PES film gave a water vapor transition rate (WVTR) of $0.062 g/m^2/day (@38^{\circ}C,\;100%\;R.H.)$. Further, the double layer of 200 nm $SiN_x$ film deposited by plasma enhanced chemical vapor deposition (PECVD) and 20 nm $AlO_x$ film by ALD resulted in a WVTR value lower than the detection limit of MOCON. We have investigated the OLED encapsulation performance of the double layer using the OLED structure of ITO / MTDATA (20 nm) / NPD (40 nm) / AlQ (60 nm) / LiF (1 nm) / Al (75 nm) on a plastic substrate. The preliminary life time to reach 91% of the initial luminance $(1300 cd/m^2)$ was 260 hours for the OLED encapsulated with 100 nm of PECVD-deposited $SiN_x$ and 30 nm of ALD-deposited $AlO_x$.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.9
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• pp.556-558
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• 2005

The effect of high irradiation on inspection systems in a nuclear power plant can be severe, especially to electronic components such as control hoards. The effect may lead to a critical malfunction or trouble to a underwater robot for inspection and maintenance of nuclear reactor. However, if information on the total accumulated dose on the sensitive parts of the robot is available, a prediction of robot's behavior in radiation environments becomes possible. To know how much radiation the robot has encountered, a dosimeter to measure the total accumulated dose is necessary. This paper describes the development effort of a dual radiation monitoring system using a SiC diode as a dose-rate meter and a p-type power MOSFET as a dose meter. This attempt using two sensors which detect same radiation improves reliability and stability at high intensity radiation detection in nuclear facilities. It uses the concept of diversity and redundancy.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.1
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• pp.21-26
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• 2003

4H-SiC Schottky rectifiers were exposed to pure Ar discharges in a planar coil Inductively Coupled Plasma system, as a function of source power, of chuck power and process pressure. The reverse breakdown voltage ($V_B$) decreased as a result of plasma exposure due to the creation of surface defects associated with the ion bombardment. The magnitude of the decrease was a function of both ion flux and ion energy. The forward turn-on voltage ($V_F$), on-state resistance ($R_{ON}$) and diode ideality factor (n) all increased after plasma exposure. The changes in all of the rectifier parameters were minimized at low power, high pressure plasma conditions.

• Journal of IKEEE
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• v.26 no.2
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• pp.306-312
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• 2022

We investigated electrical properties and deep level traps in 4H-SiC merged PiN Schottky (MPS) diodes with different barrier heights by different PN ratios and metallization annealing temperatures. The barrier heights of MPS diodes were obtained in IV and CV characteristics. The leakage current increased with the lowering barrier height, resulting in 10 times larger current. Additionally, the deep level traps (Z_1/2 and RD_1/2) were revealed by deep level transient spectroscopy (DLTS) measurement in four MPS diodes. Based on DLTS results, the trap energy levels were found to be shallow level by 22~28% with lower barrier height It could confirm the dependence of the defect level and concentration determined by DLTS on the Schottky barrier height and may lead to incorrect results regarding deep level trap parameters with small barrier heights.