• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1581-1584
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• 2008

In dual-polycide-gate structure with butting contact, net doping concentration of polysilicon was decreased due to overlap between $n^+$ and $p^+$ and lateral dopant diffusion in silicide/polysilicon layers. The generation of parasitic Schottky diode in butting contact region is attributed both to the $CoSi_2$-loss due to $CoSi_2$ agglomeration and to the decrease in net doping concentration of polysilicon layer. Parasitic Schottky diode reduces noise margin of sense amplifier in DDI DRAM, which causes column fail. The column fail could be reduced by physical isolation of $n^+/p^+$ polysilicon junction or suppressing $CoSi_2$ agglomeration by using nitrogen implantation into $p^+$ polysilicon before $CoSi_2$ formation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.191-192
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• 2005

The reverse breakdown voltages of 4H-SiC SBD(schottky barrier diode)s with FP(Field Plate) and/or FLR(Field Limiting Ring) as a edge termination, were investigated. The breakdown voltages of SBDs with FP ware investigated varying the overlap width from $1{\mu}m$ to $30{\mu}m$. The maximum average breakdown voltages was 475V. There is no significant changes for the devices with overlap width of between $5{\mu}m\sim30{\mu}m$. It was confirmed that the dielectric breakdown of the thin thermal oxide is main cause of device failure. However, the breakdown voltage of SBD with FLR was 1400V even though the FLR edge termination structure was not optimized.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.201-208
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• 2023

The dependence of the electrical characteristics on the fast neutron fluence of an epitaxial 4H-SiC Schottky barrier diode (SBD) was investigated. The 30 MeV cyclotron was used for fast neutron irradiation. The neutron fluences evaluated through Monte Carlo simulation were in the 2.7 × 10¹¹ to 1.45 × 10¹³ neutrons/cm² range. Current-voltage and capacitance-voltage measurements were performed to characterize the samples by extracting the parameters of the irradiated SBDs. Neutron-induced defects in the epitaxial layer were identified and quantified using a deep-level transient spectroscopy measurement system developed at the Korea Atomic Energy Research Institute. As the neutron fluence increased from 2.7 × 10¹¹ to 1.45 × 10¹³ neutrons/cm², the concentration of the Z_1/2 defects increased by approximately 20 times. The maximum defect concentration was estimated as 1.5 × 10¹⁴ cm^-3 at a neutron fluence of 1.45 × 10¹³ neutrons/cm².

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.10
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• pp.25-34
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• 2002

In this paper, silicidation induced Schottky contact area was obtained using the current voltage(I-V) characteristics of shallow cobalt silicided p+-n and n+-p junctions. In reverse bias region, Poole-Frenkel barrier lowering influenced predominantly the reverse leakage current, masking thereby the effect of Schottky contact formation. However, Schottky contact was conclusively shown to be the root cause of the modified I-V behavior of n+-p junction in the forward bias region. The increase of leakage current in silicided n+-p diodes is consistent with the formation of Schottky contact via cobalt slicide penetrating into the p-substrate or near to the junction area and generating trap sites. The increase of reverse leakage current is proven to be attributed to the penetration of silicide into depletion region in case of the perimeter intensive n+-p junction. In case of the area intensive n+-p junction, the silicide penetrated near to the depletion region. There is no formation of Schottky contact in case of the p+-n junction where no increase in the leakage current is monitored. The Schottky contact amounting to less than 0.01% of the total junction was extracted by simultaneous characterization of forward and reverse characteristics of silicided n+-p diode.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.2
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• pp.221-225
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• 2016

This paper reports a new method to enable the normally-off operation of AlGaN/GaN heterojunction field-effect transistors (HFETs). A capacitor was connected to the gate input node of a normally-on AlGaN/GaN HFET with a Schottky gate where the Schottky gate acted as a clamping diode. The combination of the capacitor and Schottky gate functioned as a clamp circuit to downshift the input signal to enable the normally-off operation. The normally-off operation with a virtual threshold voltage of 5.3 V was successfully demonstrated with excellent dynamic switching characteristics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.1
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• pp.29-34
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• 2008

In this paper, we investigated electrical and physical characteristics of nickel silicide using rare-earth metals(Er, Yb, Tb, Dy), Incorporated Ytterbium into Ni-silicide is proposed to reduce work function of Ni-silicide for nickel silicided schottky barrier diode (Ni-silicided SBD). Nickel silicide makes ohmic-contact or low schottky barrier height with p-type silicon because of similar work function (${\phi}_M$) in comparison with p-type silicon. However, high schottky barrier height is formed between Ni-silicide and p-type substrate by depositing thin ytterbium layer prior to Ni deposition. Even though the ytterbium is deposited below nickel, ternary phase $Yb_xN_{1-x}iSi$ is formed at the top and inner region of Ni-silicide, which is believed to result in reduction of work function about 0.15 - 0.38 eV.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.3
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• pp.111-116
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• 2004

The Ni/SiC Schottky diode was fabricated with the $\alpha$-SiC thin film grown by the ICP-CVD method on a (111) Si wafer. $\alpha$-SiC film has been grown on a carbonized Si layer in which the Si surface was chemically converted to a very thin SiC layer achieved using an ICP-CVD method at $700^{\circ}C$. To reduce defects between the Si and $\alpha$-SiC, the surface of the Si wafer was slightly carbonized. The film characteristics of $\alpha$-SiC were investigated by employing TEM (Transmission Electron Microscopy) and FT-IR (Fourier Transform Infrared Spectroscopy). Sputterd Ni thin film was used as the anode metal. The boundary status of the Ni/SiC contact was investigated by AES (Auger Electron Spectroscopy) as a function of the annealing temperature. It is shown that the ohmic contact could be acquired beyond a 100$0^{\circ}C$ annealing temperature. The forward voltage drop at 100A/cm was I.0V. The breakdown voltage of the Ni/$\alpha$-SiC Schottky diode was 545 V, which is five times larger than the ideal breakdown voltage of the silicon device. As well, the dependence of barrier height on temperature was observed. The barrier height from C- V characteristics was higher than those from I-V.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.217-221
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• 2005

The E-field intensity by mobile handsets in a phantom is measured by a 3 axes miniature probe. The detected DC voltage by a Schottky diode in a probe has nonlinear characteristics by itself. If a pertinent diode compression point (DCP) is applied for the compensation specific absorption rate(SAR) as much as 200 W/kg can be measured with a good measurement accuracy.

• Korean Journal of Materials Research
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• v.19 no.1
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• pp.28-32
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• 2009

Silicon carbide (SiC) is a promising material for power device applications due to its wide band gap (3.26 eV for 4H-SiC), high critical electric field and excellent thermal conductivity. The Schottky barrier diode is the representative high-power device that is currently available commercially. A field plate edge-terminated 4H-SiC was fabricated using a lift-off process for opening the Schottky contacts. In this case, Ni/Ti dual-metal contacts were unintentionally formed at the edge of the Schottky contacts and resulted in the degradation of the electrical properties of the diodes. The breakdown voltage and Schottky barrier height (SBH, ${\Phi}_B$) was 107 V and 0.67 eV, respectively. To form homogeneous single-metal Ni/4H-SiC Schottky contacts, a deposition and etching method was employed, and the electrical properties of the diodes were improved. The modified SBDs showed enhanced electrical properties, as witnessed by a breakdown voltage of 635 V, a Schottky barrier height of ${\Phi}_B$=1.48 eV, an ideality factor of n=1.04 (close to one), a forward voltage drop of $V_F$=1.6 V, a specific on resistance of $R_{on}=2.1m{\Omega}-cm^2$ and a power loss of $P_L=79.6Wcm^{-2}$.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.1
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• pp.41-47
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• 2015

In this paper, the effective electron Schottky barrier height (${\Phi}_{Bn}$) of the Ni silicide/n-silicon (100) interface was studied in accordance with different thicknesses of the antimony (Sb) interlayer for high performance n-channel MOSFETs. The Sb interlayers, varying its thickness from 2 nm to 10 nm, were deposited by radio frequency (RF) sputtering on lightly doped n-type Si (100), followed by the in situ deposition of Ni/TiN (15/10 nm). It is found that the sample with a thicker Sb interlayer shows stronger ohmic characteristics than the control sample without the Sb interlayer. These results show that the effective ${\Phi}_{Bn}$ is considerably lowered by the influence of the Sb interlayer. However, the current level difference between Schottky diodes fabricated with Sb/Ni/TiN (8/15/10 nm) and Sb/Ni/TiN (10/15/10 nm) structures is almost same. Therefore, considering the process time and cost, it can be said that the optimal thickness of the Sb interlayer is 8 nm. The effective ${\Phi}_{Bn}$ of 0.076 eV was achieved for the Schottky diode with Sb/Ni/TiN (8/15/10 nm) structure. Therefore, this technology is suitable for high performance n-channel MOSFETs.