Browsing by Subject "Current transport mechanism"
Now showing 1 - 4 of 4
- Results Per Page
- Sort Options
Item Open Access Current transport mechanisms and trap state investigations in (Ni/Au)-AlN/GaN Schottky barrier diodes(Elsevier, 2010-10-13) Arslan, E.; Bütün, S.; Şafak, Y.; Çakmak, H.; Yu, H.; Özbay, EkmelThe current transport mechanisms in (Ni/Au)-AlN/GaN Schottky barrier diodes (SBDs) were investigated by the use of current-voltage characteristics in the temperature range of 80-380 K. In order to determine the true current transport mechanisms for (Ni/Au)-AlN/GaN SBDs, by taking the Js(tunnel), E 0, and Rs as adjustable fit parameters, the experimental J-V data were fitted to the analytical expressions given for the current transport mechanisms in a wide range of applied biases and at different temperatures. Fitting results show the weak temperature dependent behavior in the saturation current and the temperature independent behavior of the tunneling parameters in this temperature range. Therefore, it has been concluded that the mechanism of charge transport in (Ni/Au)-AlN/GaN SBDs, along the dislocations intersecting the space charge region, is performed by tunneling. In addition, in order to analyze the trapping effects in (Ni/Au)-AlN/GaN SBDs, the capacitance-voltage (C-V) and conductance-voltage (G/ω-V) characteristics were measured in the frequency range 0.7-50 kHz. A detailed analysis of the frequency-dependent capacitance and conductance data was performed, assuming the models in which traps are located at the heterojunction interface. The density (Dt) and time constants (τt) of the trap states have been determined as a function of energy separation from the conduction-band edge (Ec - Et) as Dt≅ (5-8)×10 12eV-1 cm-2andτt≅(43-102) μs, respectively.Item Open Access Current transport mechanisms in plasma-enhanced atomic layer deposited AlN thin films(A I P Publishing LLC, 2015) Altuntas, H.; Ozgit Akgun, C.; Donmez, I.; Bıyıklı, NecmiHere, we report on the current transport mechanisms in AlN thin films deposited at a low temperature (i.e., 200°C) on p-type Si substrates by plasma-enhanced atomic layer deposition. Structural characterization of the deposited AlN was carried out using grazing-incidence X-ray diffraction, revealing polycrystalline films with a wurtzite (hexagonal) structure. Al/AlN/ p-Si metal-insulator-semiconductor (MIS) capacitor structures were fabricated and investigated under negative bias by performing current-voltage measurements. As a function of the applied electric field, different types of current transport mechanisms were observed; i.e., ohmic conduction (15.2-21.5 MV/m), Schottky emission (23.6-39.5 MV/m), Frenkel-Poole emission (63.8-211.8 MV/m), trap-assisted tunneling (226-280 MV/m), and Fowler-Nordheim tunneling (290-447 MV/m). Electrical properties of the insulating AlN layer and the fabricated Al/AlN/p-Si MIS capacitor structure such as dielectric constant, flat-band voltage, effective charge density, and threshold voltage were also determined from the capacitance-voltage measurements.Item Open Access Current transport properties of (Au/Ni)/HfAlO3/n-Si metal–insulator–semiconductor junction(Elsevier Ltd, 2020-09-11) Arslan, Engin; Badali, Yosef; Aalizadeh, Majid; Altındal, Semsettin; Ozbay, EkmelIn this study, HfAlO3 ternary alloy thin film was grown on n-type silicon using the atomic layer deposition method. The current transport mechanisms in the (Au/Ni)/HfAlO3/n-Si junction were examined over a wide temperature range (80–360 K). The values obtained for the ideality factor (n) varied from 22.93 to 3.94 and the barrier height at zero bias (ФB0) ranged from 0.221 eV to 0.821 eV as the temperature changed from 80 to 360 K. The ΦB0–n and ΦB0–q/2 kT characteristics were investigated to explain the higher n values and non-ideal behavior of the Richardson curves. Two linear regions were found at low temperatures (LTs; 80–180 K) and high temperatures (HTs; 200–360 K), which indicated the presence of a Gaussian distribution barrier height and the average barrier heights (Φ‾B0) were identified. The values obtained for Φ‾Bo were 0.734 eV for LTs and 1.125 eV for HTs, and the values of σs were 0.085 V for LTs and 0.140 V for HTs. The values obtained for Nss decreased as the temperature increased and they varied between ~1012 and 1013 eV−1 cm−2. Finally, the dielectric behavior and conductivity of the (Au/Ni)/HfAlO3/n-Si junction were investigated at frequencies between 5 kHz and 2 MHz at room temperature. The values determined for ε′ and ε′′ at −1 V and 5 kHz were 2.1 and 3.53, respectively. © 2020Item Open Access Effect of film thickness on the electrical properties of AlN films prepared by plasma-enhanced atomic layer deposition(Institute of Electrical and Electronics Engineers Inc., 2015) Altuntas, H.; Ozgit Akgun, C.; Donmez, I.; Bıyıklı, NecmiIn this paper, AlN thin films with two different thicknesses, i.e., 7 and 47 nm, were deposited at 200 °C on p-type Si substrates by plasma-enhanced atomic layer deposition using trimethylaluminum and ammonia. To investigate the electrical characteristics of these AlN films, MIS capacitor structures were fabricated and characterized using current-voltage and high-frequency (1 MHz) capacitance-voltage measurements. The results showed that the current transport mechanism under accumulation mode is strongly dependent on the applied electric field and thickness of the AlN film. Possible conduction mechanisms were analyzed, and the basic electrical parameters were extracted and compared for AlN thin films with different thicknesses. Compared with 7-nm-thick film, a 47-nm-thick AlN film showed a lower effective charge density and threshold voltage along with a higher dielectric constant.