Schottky Barrier Height Engineering of Ti/n-Type Silicon Diode by Means of Ion Implantation (original) (raw)
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Schottky Barrier Height Dependence on the Metal Work Function for p-type Si Schottky Diodes
Zeitschrift Fur Naturforschung a a Journal of Physical Sciences, 2004
We investigated Schottky barrier diodes of 9 metals (Mn, Cd, Al, Bi, Pb, Sn, Sb, Fe, and Ni) having different metal work functions to p-type Si using current-voltage characteristics. Most Schottky contacts show good characteristics with an ideality factor range from 1.057 to 1.831. Based on our measurements for p-type Si, the barrier heights and metal work functions show a linear relationship of current-voltage characteristics at room temperature with a slope (S = φ b /φ m ) of 0.162, even though the Fermi level is partially pinned. From this linear dependency, the density of interface states was determined to be about 4.5 · 10 13 1/eV per cm 2 , and the average pinning position of the Fermi level as 0.661 eV below the conduction band.
Comparison of electrical parameters of Zn/p-Si and Sn/p-Si Schottky barrier diodes
Solid State Communications, 2005
In this study, current-voltage (I-V) and capacitance-voltage (C-V) characteristics of metal-semiconductor (MS) Zn/p-Si and Sn/p-Si Schottky diodes, with high resistivity silicon structures, are investigated. The parameters of series resistance (R S), the ideality factor (n) and the barrier height (F b) are determined by performing different plots from the forward bias current-voltage (I-V) and reverse bias capacitance-voltage (C-V) characteristics. Thus, the barrier heights (F b) for the Si Schottky diodes obtained between 0.725 and 1.051 eV, the ideality factor (n) between 1.043 and 1.309, and the series resistance (R S) between 12.594 and 12.950 kU. The energy distribution of interface states density was determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height. It was concluded that the density of interface states in the considered energy range are in close agreement with each other values obtained for Zn/p-Si and Sn/p-Si Schottky diodes.
International Journal of Electronics, 2018
The main electrical characteristics of current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature of the Re/ n-type Si Schottky barrier diodes prepared by pulsed laser deposition (PLD) method have been examined. The values of the basic electrical properties such as forward saturation current (I o), ideality factors (n), barrier heights (Ф bo), rectification ratio (RR) and series resistances (R S) were obtained from I-V and C-V measurements using different calculation methods. At low voltages (V ≤ 0.3 V), the electrical conduction was formed to take place by thermionic emission, whereas at high voltages (V > 0.3 V), a space charge limited conduction mechanism was shown. Furthermore, the interface state densities (N SS) as a function of energy distribution (E SS-E V) was obtained from the I-V data by taking into account the bias dependence of the effective barrier height (Φ b) for the Re/n-type Si Schottky barrier diodes.
High-barrier height Sn/p-Si schottky diodes with interfacial layer by anodization process
We have fabricated the Sn/p-Si Schottky barrier diodes with different surface treatments. Prior to the Sn evaporation on the p-Si(0 0 1), the ®rst kinds of samples consisted of a dip in diluted aqueous HF solution followed by a rinse in de-ionized water (sample 1, SD1), the second kinds of samples several steps of anodization in aqueous KOH solution each followed by a dip in diluted aqueous HF solution and a subsequent rinse in de-ionized water (sample 2, SD2), and the third kinds of samples one anodization step only (sample 3, SD3). We have found the lowest values of both the barrier heights and ideality factors with the diodes of preparation type SD2. The anodization, on the other hand, have increased both, the barrier heights as well as the ideality factors. The extrapolation of the barrier heights versus ideality factors plot to the ideality factor determined by the image force effect have given the laterally homogeneous barrier heights of approximately 0.75 and 0.92 eV for the SD2 and SD3 diodes. Furthermore, we have calculated a mean tunneling barrier height of w 0X12 eV for the MIS Sn/p-Si diodes with the anodic oxide layer.
2009
We have studied the experimental linear relationship between ideality factors and barrier heights (BHs) for Co/n-Si metal-semiconductor (MS) structures with a doping density of about 10 15 cm −3 . The barrier heights for the Co/n-type Si metal-semiconductor structures from the current-voltage (I-V) characteristics varied from 0.64 to 0.70 eV, the ideality factor n varied from 1.18 to 1.26, and from reverse bias capacitance-voltage (C −2 -V) characteristics the barrier height varied from 0.68 to 0.81 eV. The experimental barrier height distributions obtained from the I-V and C −2 -V characteristics were fitted by a Gaussian distribution function, and their mean values were found to be 0.67 and 0.75 eV, respectively. Furthermore, the lateral homogeneous BH value of approximately 0.81 eV for Co/n-Si metal-semiconductor structures was obtained from the linear relationship between experimental effective BHs and ideality factors.
Annealing temperature effect on electrical characteristics of Co/p-type Si Schottky barrier diodes
Physica B: Condensed Matter, 2009
The electrical characteristics of Co/p-type Si Schottky barrier diodes (SBDs), which were formed at various annealing temperatures from 200 to 600 1C, were investigated using current-voltage (I-V) techniques. The Schottky barrier height at 200 1C annealing temperature was found to be 0.708 eV (I-V). However, the Schottky barrier height of the Co/p-type Si diode slightly decreases to 0.696 eV (I-V) when the diode was annealed at 300 1C for 5 min in N 2 atmosphere. It is noted that the Schottky barrier height increased to 0.765 eV at 400 1C, 0.830 eV at 500 1C and 0.836 eV at 600 1C for 5 min in N 2 atmosphere. This increase was attributed to that the annealing removes the passivation effect of the native oxide layer and reactivates the surface defects which are responsible for the Fermi level pinning. Norde method was also used to extract the barrier height of Co/p-type Si Schottky barrier diodes and the values are 0.704 eV for the 200 1C, 0.714 eV at 300 1C, 0.80447 eV at 400 1C, 0.874 eV at 500 1C and 0.874 eV at 600 1C which are in good agreement with those obtained by the I-V method.
The barrier height inhomogeneity in Al/p-Si Schottky barrier diodes with native insulator layer
Applied Surface Science, 2006
The current-voltage (I-V) characteristics of Al/p-Si Schottky barrier diodes (SBDs) with native insulator layer were measured in the temperature range of 150-375 K. The estimated zero-bias barrier height F B0 and the ideality factor n assuming thermionic emission (TE) theory show strong temperature dependence. Evaluation of the forward I-V data reveals an increase of zero-bias barrier height F B0 but decrease of ideality factor n with increase in temperature. The conventional Richardson plot exhibits non-linearity below 250 K with the linear portion corresponding to activation energy of 0.41 eV and Richardson constant (A *) value of 1.3 Â 10 À4 A cm À2 K À2 is determined from intercept at the ordinate of this experimental plot, which is much lower than the known value of 32 A cm 2 K 2 for holes in p-type Si. Such behavior is attributed to Schottky barrier inhomogene ties by assuming a Gaussian distribution of barrier heights (BHs) due to barrier height inhomogeneities that prevail at interface. Also, F B0 versus q/2kT plot was drawn to obtain evidence of a Gaussian distribution of the BHs, and values of F B0 = 1.055 eV and s 0 = 0.13 V for the mean BH and zero-bias standard deviation have been obtained from this plot, respectively. Thus, the modified ln ðI 0 =T 2 Þ À q 2 s 2 o =2k 2 T 2 versus q/kT plot gives F B0 and A * as 1.050 eV and 40.08 A cm À2 K À2 , respectively, without using the temperature coefficient of the barrier height. This value of the Richardson constant 40.03 A cm À2 K À2 is very close to the theoretical value of 32 A K À2 cm À2 for p-type Si. Hence, it has been concluded that the temperature dependence of the forward I-V characteristics of the Al/p-Si Schottky barrier diodes with native insulator layer can be successfully explained on the basis of TE mechanism with a Gaussian distribution of the barrier heights.
Tuning of Schottky barrier height of Al/n-Si by electron beam irradiation
Applied Surface Science, 2017
Highlights Tuning of Schottky barrier height can be achieved by electron beam irradiation at different doses on n-Si wafer prior to the fabrication of Schottky contact. The XPS analyses have shown irradiation induced defects and the formation of several localized chemical states in Si/SiOx interface that influences the Schottky barrier height. The thickness of the SiOx layer at the surface calculated from the intensities of XPS Si2p spectra and found to decrease with increase in the dose of electron beam irradiation. High ideality factor indicates metal-insulator-semiconductor configuration of the Schottky diode and the inhomogeneous nature of the Schottky barrier height. The Schottky barrier inhomogeneity decreases with increase in dose of electron beam radiation. The modifications in I-V characteristics as a function of electron dose is caused due to changes in the Schottky diode parameters and different transport mechanisms, such as space charge limited emission and tunneling through the trap states that are competing with the thermionic emission of electron.
Influence of the Schottky barrier height on the silicon solar cells
— With the recent introduction of ion implantation in the photovoltaic industry, it is now easier to carefully tailor the emitter doping profile. However the metallization layout should be optimized in the same time, as they are closely linked via the metal/silicon contact resistivity. In this work, an advanced co-optimization procedure allows finding out the influence of the Schottky barrier height on the metal grid design and the optimal doping profile. The theoretical electrical properties of a 2 x 2 cm² ideal silicon solar cell are also computed for each optimal combination. According to this work, the maximal achievable efficiency decreases from 26.2 % to 25.3 % if the Schottky barrier height increases from 0.5 eV to 0.9 eV.
Minority Carrier Injection in High-Barrier Si-Schottky Diodes
IEEE Transactions on Electron Devices, 2018
In this paper, we investigate the presence of minority carriers and their role in charge carrier transport in silicon (Si) Schottky diodes with a high potential barrier. Using TCAD simulations along with an analytical model, we show that an inversion charge is induced at the metal-semiconductor (MS) interface in a high-barrier Schottky diode which imparts bipolar-type current characteristics to otherwise a unipolar Schottky diode, even at low-injection operation. In such a high-barrier diode, minority diffusion also becomes important along with the majority carrier thermionic emission and therefore cannot be neglected, unlike in a conventional Schottky diode. The presence of minority carriers at low injection in a high-barrier Si Schottky diode has been experimentally verified via a prior-reported two-diode electrical test method, reverse recovery measurements, and by measuring infrared electroluminescence. It is also shown, via TCAD simulations, that the diffusion component becomes more pronounced in case of a reduced Gummel number and at elevated temperatures.