Si Schottky Barrier Diodes Research Articles

Low-frequency noise in Au-decorated graphene–Si Schottky barrier diode at selected ambient gases

We report results of the current–voltage characteristics and low-frequency noise in Au nanoparticle (AuNP)-decorated graphene–Si Schottky barrier diodes. Measurements were conducted in ambient air with addition of either of two organic vapors, tetrahydrofuran [(CH2)4O; THF] and chloroform (CHCl3), as also during yellow light illumination (592 nm), close to the measured particle plasmon polariton frequency of the Au nanoparticle layer. We observed a shift of the DC characteristics at forward voltages (forward resistance region) when tetrahydrofuran vapor was admitted (in a Au-decorated graphene–Si Schottky diode), and a tiny shift under yellow irradiation when chloroform was added (in not decorated graphene–Si Schottky diode). Significantly larger difference in the low-frequency noise was observed for the two gases during yellow light irradiation, compared with no illumination. The noise intensity was suppressed by AuNPs when compared with noise in graphene–Si Schottky diode without an AuNP layer. We conclude that flicker noise generated in the investigated Au-decorated Schottky diodes can be utilized for gas detection.

The investigation of interlayer (CeO2:PVC) effects on the dielectric features of Au-Si (MS) Schottky barrier diodes (SBDs) using the impedance spectroscopy method

In this research, Au-PVC-Si (MPS1), Au-(CeO2: PVC)-Si (MPS2) Schottky barrier diodes (SBDs) have been grown on n-type silicon (n-Si) with the aim of investigating the frequency dependence and the effect of polymer interlayer on dielectric parameters such as complex dielectric constant (ε = ε′–iε″), ac-conductivity (σ ac), and complex electric-modulus (M = M′ + iM″). For this purpose, the mentioned parameters have been calculated by measuring C/G-f in wide-range frequency (100 Hz–1 MHz) at room temperature for all three diodes and how the effect of PVC and (CeO2: PVC) interlayer on dielectric parameters of Au-Si (MS) has been studied. In the low-frequency range, plot C-f shows a negative capacitance behavior (NC) that causes the dielectric constant to be negative in this frequency range. Such negative behavior can be described using capture and emissions of carriers at interface states. The results of examining the frequency dependence of dielectric parameters showed that these parameters are sensitive to the frequency, especially the low-frequency range, which is due to the surface polarization and interface states. Also, the conduction mechanism of samples was investigated through the slope of the lnσ ac- lnω plot. The σ ac value for all three diodes at low frequencies is almost independent of the frequency, which is related to dc conductivity (σ dc). The slope value of the lnσ ac- lnω plot in the high frequencies was smaller than the unit which can be described by the hopping mechanism. The presence of the PVC and (PVC: CeO2) interlayer in the metal-semiconductor junction has increased the dielectric constant and conductivity of MPS compared to MS-type SBDs.

Thermal sensitivity and current-voltage-temperature characteristics in Pt/epitaxy n-Si/n+Si structures as a function of Schottky contact area

We have investigated the thermal sensitivity of Pt/epitaxy n-Si/n+Si Schottky barrier (SB) diodes as a function of the Schottky contact (SC) area. Moreover, we have reported the current-voltage (I-V) of these SB diodes in the temperature range of 40–320 K. The V-T characteristics for the thermal sensitivity have been measured in the 20–320 K range with steps of 2 K at different current levels, which range from 10 nA to 100 μA. The V-T curves have given two linear regions at each current level, one in the low temperature (LT) region and the other in the high temperature (HT) region. The thermal sensitivity coefficient α has increased with the decreasing current level for all diodes. The α value has increased with increasing SC area at the same current level in the LT region. The case may be attributed to the barrier inhomogeneity at low temperatures. However, in the HT region, the α value has decreased very slightly with increasing SC area at the same current level, which may be ascribed to the fact that the current transport occurs over a lateral homogeneous SB height at high temperatures. The SB height and ideality factor n values from the I-V-T curves have remained approximately unchanged from 170 to 320 K.

Determination of the leakage current transport mechanisms in quasi-vertical GaN–on–Si Schottky barrier diodes (SBDs) at low and high reverse biases and varied temperatures

Temperature-dependent current–voltage characteristics was measured to investigate leakage conduction mechanisms in GaN-on-Si quasi-vertical Schottky barrier diode. At low reverse bias, thermionic emission is dominated. At voltage range from −1 to −20 V, variable range hopping (VRH) is main leakage current mechanism at low temperatures (298–373 K), while at high temperatures (498–573 K), electrons gain enough energy and emit into the trapped states, Frenkel–Poole emission becomes dominant. At a relatively high voltage range, the increased electric field promotes the electron hopping along the threading dislocation in the bulk GaN layers, and VRH becomes the main current mechanism at whole measured temperature range (298–573 K).

Temperature dependent Schottky barrier characteristics of Al/n-type Si Schottky barrier diode with Au–Cu phthalocyanine interlayer

The Al/n-type Si Schottky barrier diodes (SBDs) were prepared with Au-Cu phthalocyanine (Au-CuPc) interlayers with different Au and CuPc compositional ratios, probed their temperature dependent current-voltage (I–V) and low frequency noise properties. The Schottky barrier properties like barrier height and the ideality factor are strongly temperature dependent, implying the existence of Schottky barrier inhomogeneities. The barrier inhomogeneities was elucidated using thermionic emission theory based on the assumption of Gaussian distribution of the barrier heights. Further, a divergence in the barrier heights evaluated from the I–V characteristics and Norde's method indicates a deviation of the Al/Au–CuPc/n-type Si SBDs behavior from thermionic emission. The Richardson plot evaluated with the Gaussian distribution of barrier heights method yielded Richardson constant values close to theoretical Richardson constant of n-type Si. The room temperature current noise power spectral density (SI) of the Al/Au–CuPc/n-type Si SBDs having various Au and CuPc concentrations showed a reciprocal of frequency (1/f)γ behavior having γ values near to unity. The decrease in SI and γ with increasing Au concentration in Au-CuPc interlayers was indicative of lessening barrier inhomogeneity. This was also correlated with the decrease in the value of standard deviation derived using temperature dependent I–V characteristics. Further investigations revealed that origins of 1/f noise could be associated with the fluctuations of barrier height and carrier mobility for Al/Au–CuPc/n-type Si SBDs with lower and higher Au compositions in Au-CuPc interlayers, respectively.

A Defects-Based Model on the Barrier Height Behavior in 3C-SiC-on-Si Schottky Barrier Diodes

3C-silicon carbide (3C-SiC) Schottky barrier diodes (SBDs) on silicon (Si) substrates (3C-SiC-on-Si) have been found to suffer from excessive subthreshold current, despite the superior electrical properties of 3C-SiC. In turn, that is one of the factors deterring the commercialization of this technology. The forward current–voltage ( $I$ – $V$ ) characteristics in these devices carry considerable information about the material quality. In this context, an advanced technology computer-aided design (TCAD) model is proposed and validated with measurements obtained from a fabricated and characterized platinum/3C-SiC-on-Si SBD with scope to shed light on the physical carrier transport mechanisms, the impact of traps, and their characteristics on the actual device performance. The model includes defects originating from both the Schottky contact and the heterointerface of 3C-SiC with Si, which allows the investigation of their impact on the magnification of the subthreshold current. Furthermore, the simulation results and measured data allowed for the identification of additional distributions of interfacial states, the effect of which is linked to the observed nonuniformities of the Barrier height value. A comprehensive characterization of the defects affecting the carrier transport mechanisms of the investigated 3C-SiC-on-Si power diode is thus achieved, and the proposed TCAD model is able to accurately predict the device current both during forward and reverse bias conditions.

Comparison of electrical characteristics of Sn/p-type Si structure at different temperatures and under irradiation

Abstract In this study, we have examined effects of temperature and irradiation on the electrical properties of the Sn/p- Si Schottky barrier diodes by using the forward bias current–voltage (I–V) and capacitance–voltage (C–V) measurements. The electrical characteristics of the Schottky barrier diode have been investigated at 300 K, 400 K temperature and under 500 kGy gamma irradiation, respectively. The main parameters such as barrier heights (Φb), ideality factors (n), and series resistances (RS) were calculated using the I–V measurements. It has been seen that the device is sensitive to temperature and to gamma irradiation. This has been attributed to decrease in ionized dopant concentration with temperature. Furthermore, the interface state densities (NSS) as a function of energy distribution (ESS- EV) were extracted from the forward-bias I–V measurements

The analysis of the electrical characteristics and interface state densities of Re/n-type Si Schottky barrier diodes at room temperature

ABSTRACTThe 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 (Io), ideality factors (n), barrier heights (Фbo), rectification ratio (RR) and series resistances (RS) 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 (NSS) as a function of energy distribution (ESS- EV) was obtained from the I-V data by taking into account the bias dependence of the effective barrier height (Φb) for the Re/n-type Si Schottky barrier diodes.

On the Understanding of Cathode Related Trapping Effects in GaN-on-Si Schottky Diodes

Cathode related current collapse effect in GaN on Si Schottky barrier diodes is investigated in this paper. Capacitance and current relaxation measurements on diodes and gated-Van Der Pauw are associated with temperature dependent dynamic ${R_{\mathrm{ ON}}}$ transients analysis to identify the parasitic trapping locations in the devices. We show here that the main part of the current collapse at the cathode comes from a combination of electron trapping in the passivation layer and in a carbon related trap in the GaN buffer layers ( ${E_{A}} = \mathrm {E_{T}} - {E_{V}} \simeq 0.9 \,\mathrm {eV}$ ) that can be studied independently by using the appropriate stress configurations. These two parasitic effects can lead to long recovery time (>1 ks) after reverse bias stress.

Demonstration of fully vertical GaN‐on‐Si Schottky diode

The realisation of a fully vertical gallium nitride (GaN)-on-silicon (Si) Schottky barrier diode (SBD) without using wafer bonding and Si substrate removal process is reported. The SBD presented a turn-on voltage of 0.69 V at 1 A/cm 2 , breakdown voltage of 148 V with a specific on-resistance of 13.9 mΩ cm 2 . The ideality factor and Schottky barrier height were 1.35 and 0.71 eV, respectively. An effective critical electric field was estimated to be 1.48 MV/cm. The Baliga's figure of merit for the SBD was calculated to be 1.57 MW/cm 2 . These results indicate the great potential of GaN-on-Si in achieving cost-effective fully vertical power device.

ON-State Degradation in AlGaN/GaN-on-Silicon Schottky Barrier Diodes: Investigation of the Geometry Dependence

In this paper, we present the results of a combined measurement/simulation analysis of the degradation induced by on-state stress in Au-free AlGaN/gallium-nitride-on-Si Schottky barrier diodes (SBDs). Turn-on voltage ( $V_{\mathrm{ TON}}$ ) and on-resistance ( $R_{\mathrm{\scriptscriptstyle ON}}$ ) are affected by charge carrier trapping/detrapping, occurring in different regions and caused by different mechanisms, when a high stress current is applied to the device. In particular, we have investigated the degradation of SBDs adopting different stress conditions and analyzing the influence of the diode geometry; consequently, we were able to identify the physical mechanisms responsible for long-term degradation of $V_{\mathrm{ TON}}$ and $R_{\mathrm{\scriptscriptstyle ON}}$ . In addition, thanks to this approach, a critical electric field for the $R_{\mathrm{\scriptscriptstyle ON}}$ degradation has been determined.

Investigation of the depletion layer by scanning capacitance force microscopy with Kelvin probe force microscopy

We have developed a scanning probe microscope (SPM) that combines atomic force microscopy (AFM) with both Kelvin probe force microscopy (KFM — to measure the surface potential) and scanning capacitance force microscopy (SCFM — to measure the differential capacitance). The surface physical characteristics of a commercial Si Schottky barrier diode (Si-SBD), with and without an applied reverse bias, were measured over the same area by our AFM/KFM/SCFM system. We thus investigated the discrete power device by calculating the depletion-layer width and drawing an energy-band diagram.

Temperature Dependent Current-Voltage and Capacitance-Voltage Characteristics of an Au/n-Type Si Schottky Barrier Diode Modified Using a PEDOT:PSS Interlayer

The temperature dependence of the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of an Au/n-type Si Schottky barrier diode (SBD) with a PEDOT:PSS interlayer was investigated. The SBD parameters, such as Schottky barrier height ()B), ideality factor (n), saturation current (I0), doping concentration (ND), and series resistance (Rs), were obtained as a function of temperature. The Richardson constant (A**) obtained from the In(Io/T 2 ) versus 1000/T plot was much less than the theoretical value for n-Si. The mean Schottky barrier height ( � � bo) and standard deviation (·0) calculated using the apparent Schottky barrier height ()ap) versus 1/2kT plot were 1.26eVand 0.15eV, respectively. From a fit of the modified Richardson plot of ln(I0/T 2 ) ¹ (q·) 2 /2(kT) 2 versus 1000/T, the A** was extracted as 134A/cm 2 K 2 , which was close to the theoretical value of the n-Si. The interface state densities obtained from the Au/PEDOT:PSS/n-Si SBD decreased with increasing temperature. Furthermore, the conduction mechanism dominating the reverse-bias leakage current in Au/PEDOT:PSS/n-Si SBD was described and discussed. [doi:10.2320/matertrans.M2014263]

A 99%‐efficiency GaN converter for 6.78 MHz magnetic resonant wireless power transfer system

The authors developed a high-efficiency gallium-nitride (GaN) Class-E converter for a 6.78 MHz magnetic resonant wireless power transfer system. A negative-bias gate driver circuit made it possible to use a depletion mode GaN high-electron-mobility transistor (HEMT), and simplified the converter circuit. As the depletion mode GaN HEMT with very small gate–source capacitance provided almost ideal zero-voltage switching, the authors attained a drain efficiency of 98.8% and a total efficiency of 97.7%, including power consumption of a gate driver circuit, at a power output of 33 W. In addition, the authors demonstrated a 6.78 MHz magnetic resonant wireless power transfer system that consisted of the GaN Class-E converter, a pair of magnetic resonant coils 150 mm in diameter with an air-gap distance of 40 mm, and a full-bridge rectifier using Si Schottky barrier diodes. The system achieved a dc–dc efficiency of 82.8% at a power output of 25 W. The efficiencies of coil coupling and the rectifier were estimated to be ∼ 94 and 90%, respectively.

Low onset voltage of GaN on Si Schottky barrier diode using various recess depths

A low onset voltage AlGaN/GaN diode with a width of 14 mm is achieved. The recess depth of the AlGaN layer is responsible for the low onset voltage. In comparison with the conventional non-recessed diode, the onset voltage reduces by 45% along with a decrease of reverse leakage current by about one order of magnitude.

Microwave building as an application of wireless power transfer

We propose a wireless power distribution system (WPDS) operating at 2.45 GHz CW in buildings instead of wired power distribution in order to reduce the initial cost of the building. Required technologies for the WPDS are (a) low-cost and low-loss deck plate waveguide, (b) variable microwave power distributor for the waveguide, and (c) high-power (>100 W) rectifier at the outlet. We developed and tested the deck plate waveguide, power distributor, and high-power rectenna consisting of 256 Si Schottky barrier diodes and newly developed GaN diodes. Finally, a test WPDS was built and microwave power transmission experiments were conducted. The total efficiency of the test WPDS was estimated to be 52%.

Electrical properties and interface state energy distributions of Cr/n-Si Schottky barrier diode

In this study, the electrical characteristics of the Cr/n-type Si (MS) Schottky barrier diode have been investigated by the current–voltage (I–V) and capacitance–voltage (C–V) measurements at 300K temperature. Using the thermionic emission theory, the values of ideality factor and the barrier height have been obtained to be 1.22, 0.71 and 1.01, 0.83eV, from the results of the I–V and C–V measurements, respectively. The barrier height (Φb) and the series resistance (RS) obtained from Norde’s function have been compared with those obtained from Cheung functions, and a good agreement between the results of both methods was seen. The interface state density (NSS) calculated without the RS is obtained to be increasing exponentially with bias from 2.40×1012cm−2eV−1 in (EC−0.623) eV to 1.94×1014cm−2eV−1 in (EC−0.495) eV, also, the NSS obtained taking into account the RS has increased exponentially with bias from 2.07×1012cm−2eV−1 to 1.47×1014cm−2eV−1 in the same interval.

Schottky barrier diode parameters of Ag/MgPc/p-Si structure

An Ag /Pc/p- Si Schottky barrier (SB) diode was fabricated. The current-voltage (I-V), capacitance-voltage (C-V) and conductance-voltage (G-V) measurements were carried out to determine the characteristic parameters such as barrier height, ideality factor and series resistance of the SB diode. The non-linear behavior of ln (I) vs. ln (V) and ln (I/V) vs. V1/2 plots indicated that the thermoionic emission theory can be applied to evaluate junction parameters for the investigated SB diode rather than space-charge limited conduction (SCLC) mechanism and bulk-limited Poole–Frenkel emission. The bulk doping concentration NB and fixed oxide charges Nf was determined from the measured high frequency C-V curve and was found to be 9.5 × 1014 cm-3 and 2.3 × 1013 cm-2, respectively. The values of barrier height obtained from Norde's function were compared with those from the forward bias current-voltage characteristic, and it was seen that there was a good agreement between barrier heights from both methods.

Temperature characteristics of Schottky barrier diodes for low-voltage sensing applications

N-type Si Schottky barrier diodes (SBDs) have been fabricated in AMI 0.5 m process. The I-V characteristics have been characterised from -50 to 120-C. The bias voltages for achieving the zero temperature coefficient (ZTC) point were observed to be around 0.6-V, which are much smaller than the voltages for metal-oxide-semiconductor field-effective transistors (MOSFETs) to obtain the same point. A physical model was extracted for the SBDs, demonstrating the low ZTC-point-bias-voltages which are advantageous for low-voltage applications.

Investigation on a radiation tolerant betavoltaic battery based on Schottky barrier diode

An Au-Si Schottky barrier diode was studied as the energy conversion device of betavoltaic batteries. Its electrical performance under radiation of Ni-63 and H-3 sources and radiation degradation under Am-241 were investigated and compared with those of the p-n junction. The results show that the Schottky diode had a higher I(sc) and harder radiation tolerance but lower V(oc) than the p-n junction. The results indicated that the Schottky diode can be a promising candidate for energy conversion of betavoltaic batteries.