Browsing by Subject "Negative capacitance"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    The effect of insulator layer thickness on the main electrical parameters in (Ni/Au)/AlxGa1-xN/AIN/GaN heterostructures
    (Wiley, 2010) Altindal, S.; Şafak, Y.; Taşçloǧlu I.; Özbay, Ekmel
    (Ni/Au)Alx Ga1-x N/AlN/GaN(x = 0.22) heterostructures with and without a passivation layer of the SiNx were fabricated in order to see the effect of the insulator layer on the main electrical parameters such as zero-bias barrier height (BH) (φBO), ideality factor (n), series resistance (Rs) of the structure, and the interface state density (Nss). Some of these parameters were determined from both I-V and admittance (C-V and G/ω-V) measurements at room temperature and at 1 MHz and were compared. The experimental results show that the value of N ss in a Schottky contact without passivation is nearly 1 order of magnitude larger than that in a Schottky contact with SiNx passivation layers. Also, the values of Rs increase with the increasing thickness of the passivation layer. In the forward bias region, the negative values of capacitance are an attractive result of this study. This negative capacitance disappears in presence of the passivation layer. Copyright © 2010 John Wiley & Sons, Ltd.
  • Thumbnail Image
    ItemOpen Access
    Temperature-dependent profile of the surface states and series resistance in (Ni/Au)/AIGaN/AIN/GaN heterostructures
    (Wiley, 2010-03-28) Taşçıoğlu, I.; Aydemir, U.; Şafak, Y.; Özbay, Ekmel
    The profile of the interface state densities(N ss) and series resistances (R s) effect on capacitance-voltage (C-V) and conductancevoltage (G/ω-V) of (Ni/Au)/Al xGa 1-xN/AIN/ GaN heterostructures as a function of the temperature have been investigated at 1 MHz. The admittance method allows us to obtain the parameters characterizing the metal/semiconductor interface phenomena as well as the bulk phenomena. The method revealed that the density of interface states decreases with increasing temperature. Such a behavior of N ss can be attributed to reordering and restructure of surface charges. The value of series R s decreases with decreasing temperature. This behavior of R s is in obvious disagreement with that reported in the literature. It is found that the N ss and R s of the structure are important parameters that strongly influence the electrical parameters of (Ni/Au)/Al xGa 1-XN/AlN/GaN(x = 0.22) heterostructures. In addition, in the forward bias region a negative contribution to the capacitance C has been observed, that decreases with the increasing temperature.