Accurate surface potential determination in Schottky diodes by use of correlated current and capacitance voltage measurements. Application to n–InP

Based on current voltage (I-V_g) and capacitance voltage (C-V_g) measurements, a reliable procedure is proposed to determine the effective surface potential V_d.V_g/ in Schottky diodes. In the framework of thermionic emission, our analysis includes both the effect of the series resistance and the ideality factor, even voltage dependent. This technique is applied to n-type indium phosphide (n-InP) Schottky diodes with and without an interfacial layer and allows us to provide an interpretation of the observed peak on the C-V_g measurements. The study clearly shows that the depletion width and the flat band barrier height deduced from C-V_g, which are important parameters directly related to the surface potential in the semiconductor, should be estimated within our approach to obtain more reliable information.     

Accurate surface potential determination in Schottky diodes by the use of a correlated current and capacitance voltage measurements.Application to n-InP

Based on current voltage(I-V_g) and capacitance voltage(C-V_g) measurements,a reliable procedure is proposed to determine the effective surface potential V_d(V_g) in Schottky diodes.In the framework of thermionic emission,our analysis includes both the effect of the series resistance and the ideality factor,even voltage dependent. This technique is applied to n-type indium phosphide(n-InP) Schottky diodes with and without an interfacial layer and allows us to provide an interpretation of the observed peak on the C-V_g measurements.The study clearly shows that the depletion width and the flat band barrier height deduced from C-V_g,which are important parameters directly related to the surface potential in the semiconductor,should be estimated within our approach to obtain more reliable information.     

Dielectric properties and ac electrical conductivity studies of MIS type Schottky diodes at high temperatures

Dielectric properties and ac electrical conductivity of the Al/SiO₂/p-Si (MIS) Schottky diodes were studied in the frequency and temperature range of 10 kHz-1 MHz and 300-400 K, respectively. Experimental results show that the dielectric constant (ε′), dielectric loss (ε″), loss tangent (tan δ), ac electrical conductivity (σ_ac) and the electric modulus were found a strong function of frequency and temperature. The values of the ε′, ε″ and tan δ decrease with increasing frequencies due to the interface states capacitance and a decrease in conductance with increasing frequency. Also, these values increase with increasing temperature. The σ_ac is found to increase with increasing frequency and increasing temperature. The variation of conductivity as a function of temperature and frequency reveals non-adiabatic hopping of charge carriers between impurities localized states. In addition, the experimental dielectric data have been analyzed by considering electric modulus formalism.     

Temperature dependent electrical and dielectric properties of Au/polyvinyl alcohol (Ni, Zn-doped)/n-Si Schottky diodes

The electrical and dielectric properties of Au/PVA (Ni, Zn-doped)/n-Si Schottky diodes (SDs) were studied in the temperature range of 80-400 K. The investigation of various SDs fabricated with different types of interfacial layer is important for understanding the electrical and dielectric properties of SDs. Therefore, in this study polyvinyl alcohol (PVA) film was used as an interfacial layer between metal and semiconductor. The electrical and dielectric properties of Au/PVA (Ni, Zn-doped)/n-Si SDs were calculated from the capacitance-voltage (C-V) and conductance-voltage (G/w-V) measurements. The effects of interface state density (N_ss) and series resistance (R_s) on C-V characteristics were investigated in the wide temperature range. It was found that both of the C-V-T and G/w-V-T curves included two abnormal regions and one intersection point. The dielectric constant (ε″), dielectric loss (ε″), dielectric loss tangent (tan δ) and the ac electrical conductivity (σ_ac) obtained from the measured capacitance and conductance were studied for Au/PVA (Ni, Zn-doped)/n-Si SDs. Experimental results show that the values of ε′, ε″ and tan δ are a strong function of the temperature. Also, the results indicate the interfacial polarization can be more easily occurred at high temperatures.     

Structural, electrical and magnetic characterizations of Ni/Cu/p-Si Schottky diodes prepared by liquid phase epitaxy

In this paper, we have investigated the structural, electrical and magnetic characterizations of Ni/Cu/p-Si Schottky diode prepared by liquid phase epitaxy (LPE). Current density-voltage (J-V), capacitance-voltage (C-V) and capacitance-frequency (C-f) measurements were performed to determine the conduction mechanisms as well as extracting the important diode parameters. Rectifying properties were obtained, which definitely of the Schottky diode type. At low voltages, (0 < V ? 0.4 V), current density in the forward direction was found to obey the diode equation, while for higher voltages, (0.5 < V ? 1.5 V), conduction was dominated by a space-charge-limited conduction (SCLC) mechanism. Analysis of the experimental data under reverse bias suggests a transition from electrode-limited to a bulk-limited conduction process for lower and higher applied voltages, respectively. Diode parameters such as, the built-in potential, V_b, the carrier concentration, N, the width of the depletion layer, W, of the Ni/Cu/p-Si Schottky diode were obtained from the C-V measurements at high frequency (1 MHz). The capacitance-frequency measurements showed that the values of capacitance were highly frequency dependent at low frequency region but independent at high frequencies. The Ni/Cu/p-Si Schottky diode showed magnetic properties due to the effect of Ni in the heterostructure.     

The source of negative capacitance and anomalous peak in the forward bias capacitance-voltage in Cr/p-si Schottky barrier diodes (SBDs)

The frequency and voltage dependence of capacitance–voltage (C–V) and conductance-voltage (G/ω−V) characteristics of the Cr/p-Si metal semiconductor (MS) Schottky barrier diodes (SBDs) were investigated in the frequency and applied bias voltage ranges of 10 kHz to 5 MHz and (−4 V)−(+4 V), respectively, at room temperature. The effects of series resistance (R_s) and density distribution of interface states (N_ss), both on C–V and G/ω−V characteristics were examined in detail. It was found that capacitance and conductance, both, are strong functions of frequency and applied bias voltage. In addition, both a strong negative capacitance (NC) and an anomalous peak behavior were observed in the forward bias C–V plots for each frequency. Contrary to the behavior of capacitance, conductance increased with the increasing applied bias voltage and there happened a rapid increase in conductance in the accumulation region for each frequency. The extra-large NC in SBD is a result of the existence of R_s, N_ss and interfacial layer (native or deposited). In addition, to explain the NC behavior in the forward bias region, we drew the C–I and G/ω−I plots for various frequencies at the same bias voltage. The values of C decrease with increasing frequency at forward bias voltages and this decrease in the NC corresponds to an increase in conductance. The values of N_ss were obtained using a Hill–Coleman method for each frequency and it exhibited a peak behavior at about 30 kHz. The voltage dependent profile of R_s was also obtained using a Nicollian and Brews methods.     

Schottky barrier height studies of Au/4H-SiC(0001) using photoemission and synchrotron radiation

The Schottky barrier height (SBH) of Au on 4H-SiC(0001) has been studied using photoemission and synchrotron radiation. The Au was deposited in-situ on clean and well-ordered √3×√3 R30° reconstructed SiC surfaces prepared by in situ heating at ∼950°C. The SBH was determined from the shift observed in the Si 2p core level, in addition to the initial band bending determined for the clean surface. The results were compared with values obtained by electrical, capacitance-voltage (C-V), and current-voltage (I-V) characterization methods. A favorable comparison between the three independent, SBH determination methods was found.     

Frequency and voltage dependence of admittance characteristics of Al/Al2O3/PVA:n-ZnSe Schottky barrier diodes

This paper reports the frequency dependence of admittance measurements i.e C–V and G/ω–V characteristics of Al/Al₂O₃/PVA:n-ZnSe MIS diode. The interface states (N_ss) and series resistance (R_s) of the MIS diode strongly influence the C–V–f and G/ω–V–f characteristics. The conductance method is used to calculate the series resistance (R_s), the density of states (N_ss), insulator layer capacitance and thickness. The frequency dependent dieclectric parameters such as dielectric constant (εʹ), dielectric loss (ε″), loss tangent (tan δ) and a.c. electrical conductivity (σ_ac) has been calculated and which are also responsible for observed frequency dispersion in C–V and G/ω curves.     

Temperature dependent current–voltage (I–V) characteristics of Au/n-Si (1 1 1) Schottky barrier diodes with PVA(Ni,Zn-doped) interfacial layer

Current–voltage (I–V) characteristics of Au/PVA/n-Si (1 1 1) Schottky barrier diodes (SBDs) have been investigated in the temperature range 80–400 K. Here, polyvinyl alcohol (PVA) has been used as interfacial layer between metal and semiconductor layers. The zero-bias barrier height (Φ_B0) and ideality factor (n) determined from the forward bias I–V characteristics were found strongly dependent on temperature. The forward bias semi-logarithmic I–V curves for different temperatures have an almost common cross-point at a certain bias voltage. The values of Φ_B0 increase with the increasing temperature whereas those of n decrease. Therefore, we have attempted to draw Φ_B0 vs. q/2kT plot in order to obtain evidence of a Gaussian distribution (GD) of the barrier heights (BHs). The mean value of BH and standard deviation (σ₀) were found to be 0.974 eV and 0.101 V from this plot, respectively. Thus, the slope and intercept of modified vs. q/kT plot give the values of and Richardson constant (A^?) as 0.966 eV and 118.75 A/cm²K², respectively, without using the temperature coefficient of the BH. This value of A^* 118.75 A/cm²K² is very close to the theoretical value of 120 A/cm²K² for n-type Si. Hence, it has been concluded that the temperature dependence of the forward I–V characteristics of Au/PVA/n-Si (1 1 1) SBDs can be successfully explained on the basis of the Thermionic Emission (TE) theory with a GD of the BHs at Au/n-Si interface.     

Frequency and temperature dependence of the dielectric and AC electrical conductivity in (Ni/Au)/AlGaN/AlN/GaN heterostructures

The dielectric properties and AC electrical conductivity (σ_ac)of the (Ni/Au)/Al_0.22Ga_0.78N/AlN/GaN heterostructures, with and without the SiN_x passivation, have been investigated by capacitance-voltage and conductance-voltage measurements in the wide frequency (5kHz-5 MHz) and temperature (80-400 K) range. The experimental values of the dielectric constant (ε′), dielectric loss (ε′′), loss tangent (tanδ), σ_ac and the real and imaginary part of the electric modulus (M′ and M′′) were found to be a strong function of frequency and temperature. A decrease in the values of ε′ and ε′′ was observed, in which they both showed an increase in frequency and temperature. The values of M′ and M′′ increase with increasing frequency and temperature. The σ_ac increases with increasing frequency, while it decreases with increasing temperature. It can be concluded, therefore, that the interfacial polarization can occur more easily at low frequencies and temperatures with the number of interface states density located at the metal/semiconductor interface. It contributes to the ε′ and σ_ac.     

Electrical properties of Ge metal–oxide–semiconductor capacitors with high-k La2O3 gate dielectric incorporated by N or/and Ti

LaON, LaTiO and LaTiON films are deposited as gate dielectrics by incorporating N or/and Ti into La2O3 using the sputtering method to fabricate Ge MOS capacitors, and the electrical properties of the devices are carefully examined. LaON/Ge capacitors exhibit the best interface quality, gate leakage property and device reliability, but a smaller k value (14.9). LaTiO/Ge capacitors exhibit a higher k value (22.7), but a deteriorated interface quality, gate leakage property and device reliability. LaTiON/Ge capacitors exhibit the highest k value (24.6), and a relatively better interface quality (3.1E11 eV^-1cm^-2), gate leakage property (3.6E3 A/cm^2 at Vg = 1 V + Vfb) and device reliability. Therefore, LaTiON is more suitable for high performance Ge MOS devices as a gate dielectric than LaON and LaTiO materials.