• Korean Journal of Materials Research
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• v.12 no.9
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• pp.724-728
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• 2002

Inductively-coupled $N_2$O plasma was utilized to grow silicon dioxide at low temperature and applied to fabricate polycrystalline-silicon thin film transistors. At $400^{\circ}C$, the thickness of oxide was limited to 5nm and the oxide contained Si≡N and ≡Si-N-Si≡ bonds. The nitrogen incorporation improved breakdown field to 10MV/cm and reduced the interface charge density to $1.52$\times$10^{11}$ $cm^2$ with negative charge. The $N_2$O plasma gate oxide enhanced the field effect mobility of polycrystalline thin film transistor, compared to $O_2$ plasma gate oxide, due to the reduced interface charge at the $Si/SiO_2$ interface and also due to the reduced trap density at Si grain boundaries by nitrogen passivation.

• Electrical & Electronic Materials
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• v.7 no.3
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• pp.231-235
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• 1994

The multi-dielectric layer $SiO_2$/$Si_3{N_4}$/$SiO_2$ (ONO) is used to improve charge retention and to scale down the memory device. The nitride layer of MNOS device is oxidize to form ONO system. During the oxidation of the nitride layer, the change of thickness of nitride layer and generation of interface state between nitride layer and top oxide layer occur. In this paper, effects of oxidation of the nitride layer is studied. The decreases of the nitride layer due to oxidation and trapping characteristics of interface state of multi layer dielectric film are investigated through the C-V measurement and F-N tunneling injection experiment using SONOS capacitor structure. Based on the experimental results, carrier trapping model for maximum flatband voltage shift of multi layer dielectric film is proposed and compared with experimental data. As a results of curve fitting, interface trap density between the top oxide and layer is determined as being $5{\times}10^11$~$2{\times}10^12$[$eV^1$$cm^2$].

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.593-596
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• 1998

Effects of current re-stress after anneal on leakage current and trapped charges in oxides are investigated. Current stress on 6 nm thick oxide has generated mostly positive traps within the oxide resulting in leakage currents. The interface states generated are several orders of magnitude smaller, determined by C-V and charge pumping method. Annealing has eliminated only the charged traps not the neutral traps, thus the leakage current and trap density are increased when the oxides are re-stressed.

• Journal of the Korean Vacuum Society
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• v.20 no.2
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• pp.93-99
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• 2011

We investigated how the surface roughness of electrode affects the charge injection at the pentacene/Au interface. After depositing Au film on the Si substrate by sputtering, we annealed the sample to control the Au surface roughness. Pentacene and Au top electrode were subsequently deposited to complete the sample. The nucleation density of pentacene was slightly higher on the rougher Au electrode, but surface morphologies of thick pentacene films were similar on both the as-prepared and the roughened Au electrodes. The current-voltage curves obtained from the Au/pentacene/Au structure measured as a function of temperature indicated that the interface barrier was higher for the rougher Au bottom-electrode. We propose that the higher barrier was caused by the lower work function of rougher electrode surface and the higher trap density at the interface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.53-53
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• 2009

Charge trap flash memory devices with modified tunneling barriers were fabricated using the tunneling barrier engineering technique. Variable oxide thickness (VARIOT) barrier and CRESTED barrier consisting of thin $SiO_2$ and $Si_3N_4$ dielectric layers were used as engineered tunneling barriers. The VARIOT type tunneling barrier composed of oxide-nitride-oxide (ONO) layers revealed reliable electrical characteristics; long retention time and superior endurance. On the other hand, the CRESTED tunneling barrier composed of nitride-oxide-nitride (NON) layers showed degraded retention and endurance characteristics. It is found that the degradation of NON barrier is associated with the increase of interface state density at tunneling barrier/silicon channel by programming and erasing (P/E) stress.

• Journal of Adhesion and Interface
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• v.21 no.4
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• pp.129-134
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• 2020

Understanding charge trapping at the interface between conjugated semiconductor and polymer dielectric basically gives insight into the development of long-term stable organic field-effect transistors (OFET). Here, the charge transport properties of OFETs using polymer dielectric with various molecular weights (MWs) have been investigated. The conjugated semiconductor, pentacene exhibited morphology and crystallinity, insensitive to MWs of polymethyl methacrylate (PMMA) dielectric. Consequently, transfer curves and field-effect mobilities of as-prepared devices are independent of MWs. Under bias stress in humid environment, however, the drain current decay as well as transfer curve shift are found to increase as the MW of PMMA decreases (MW effect). The charge trapping induced by MW effect is irreversible, that is, the localized charges are difficult to be delocalized. The MW effect is caused by the variation in the density of polymer chain ends in the PMMA: the free volumes at the PMMA chain ends act as charge trap sites, corresponding to drain current decay depending on MWs of PMMA.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.5
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• pp.664-674
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• 2016

The electrical properties of Ti/p-type InP Schottky diodes with and without polyaniline (PANI) interlayer was investigated using current-voltage (I-V) and capacitance-voltage (C-V) measurements. The barrier height of Ti/p-type InP Schottky diode with PANI interlayer was higher than that of the conventional Ti/p-type InP Schottky diode, implying that the organic interlayer influenced the space-charge region of the Ti/p-type InP Schottky junction. At higher voltages, the current transport was dominated by the trap free space-charge-limited current and trap-filled space-charge-limited current in Ti/p-type InP Schottky diode without and with PANI interlayer, respectively. The domination of trap filled space-charge-limited current in Ti/p-type InP Schottky diode with PANI interlayer could be associated with the traps originated from structural defects prevailing in organic PANI interlayer.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.44 no.4
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• pp.483-489
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• 1995

To investigate the mechanism generated by irradiation in the insulator layer irradiated MIS (Metal - Insulator - Semiconductor) device, the various types of MIS capacitors depending on insulator thickness, insulator types and implanted impurities are fabricated on the P-type wafer. MIS capacitors exposed by 1Mrad Co$^{60}$ .gamma.-ray are measured for flat band voltage and charge density shifts pre- and post-irradiation. The measuring results of post-irradiation show the flat band voltage shifting toward negative direction and charge density increasing regardless of parameters. This results have a good agreement with calculated data by computer simulation. Si$_{3}$N$_{4}$ layers have a good radiation-hardness than SiO$_{2}$ layers compared to the results of post-irradiation. Also, radiation-induced negative trap is discovered in the implanted insulator layer. Using numerical analysis, four continuty equations (conduction-band electrons continuity equation, valence-band holes continuity equation, trapped electrons continuity equation, trapped holes continuity equation) are solved and charge distributions according to the distance and Si-Insulator interface states are investigated.

• Journal of Adhesion and Interface
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• v.21 no.3
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• pp.86-92
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• 2020

We confirmed the effects on the device performances and the charge injection characteristics of organic field-effect transistor (OFET) by selectively differently controlling the surface energies on the contact region of the substrate where the source/drain electrodes are located and the channel region between the two electrodes. When the surface energies of the channel and contact regions were kept low and increased, respectively, the field-effect mobility of the OFET devices was 0.063 ㎠/V·s, the contact resistance was 132.2 kΩ·cm, and the subthreshold swing was 0.6 V/dec. They are the results of twice and 30 times improvements compared to the pristine FET device, respectively. As the results of analyzing the interfacial trap density according to the channel length, a major reason of the improved device performances could be anticipated that the pi-pi overlapping direction of polymer semiconductor molecules and the charge injection pathway from electrode is coincided by selective surface treatment in the contact region, which finally induces the decreases of the charge trap density in the polymer semiconducting film. The selective surface treatment method for the contact region between the electrode and the polymer semiconductor used in this study has the potential to maximize the electrical performances of organic electronics by being utilized with various existing processes to lower the interface resistance.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.9
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• pp.502-509
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• 2000

In this paper in order to evaluat quantitavely the formation mechanism of space charge and its effects on the conduction characteristics in LDPE we have carried out the numerical analysis on the basis of experimental results of space charge distribution cathode field and current with time which had been simultaneously measured at applied field of 50kV/mm and room temperature. As the models for numerical analysis we employ the Richarson-Schottky theory for charge injection from electrode into LDPE and the band-tail conduction at crystalline regions and the hopping conduction by traps which mainly exist at the interface regions of crystalline-amorphous region for charge transport in LDPE. Futhermore in order to investigate the influence of physical parameters on the time characteristcs of space charge distribution and measured current we have changed the values of trap density activation energies for charge injection and transport and have analyzed their effects.