Temperature dependence of characteristic parameters of the H-terminated Sn/p-Si(1 0 0) Schottky contacts

The current - voltage (I - V) characteristics of palladium silicide-based Schottky diodes on n-type silicon have been measured over a wide temperature range (66 - 300 K). Their analysis on the basis of the thermionic emission - diffusion (TED) mechanism reveals an abnormal decrease of zero-bias barrier height and increase of ideality factor with decrease in temperature (T) and nonlinearity in the activation energy plot. Such behaviour is attributed to barrier inhomogeneities by assuming a Gaussian distribution of barrier heights at the silicide/silicon interface. Evidence is given for the existence of a double Gaussian distribution having mean barrier heights of 0.79 V and 0.64 V and standard deviations of 0.081 V and 0.057 V with ideality factors 1.064 and 1.363, and remain effective in the temperature range 134 - 300 K and 66 - 120 K respectively. Further, the effect of forward bias on the distribution parameters is discussed. A simple method, involving the use of a zero-bias barrier height versus inverse temperature plot, is suggested to deduce the presence of single/multiple distribution(s) of barrier heights and to determine the respective parameters.

https://iopscience.iop.org/article/10.1088/0268-1242/11/8/015/pdf

Evidence for the double distribution of barrier heights in Schottky diodes from I - V - T measurements

A dual-band self-powered photodetector (SPPD) with high sensitivity is realized by a facile combination of InSe Schottky diode and Au plasmonic nanoparticle (NP) arrays. Comparing with pristine InSe devices, InSe/Au photodetectors possess an additional capability of photodetection in visible to near-infrared (NIR) region. This intriguing phenomenon is attributed to the wavelength selective enhancement of pristine responsivities by hybridized quadrupole plasmons resonance of Au NPs. It is worth pointing out that the maximum of enhancement ratio in responsivity reaches up to ∼1200% at a wavelength of 685 nm. In addition, owing to a large Schottky barrier difference formed between active layer and two asymmetric electrodes, the responsivities of dual-band InSe/Au photodetector could reach up to 369 and 244 mA/W at the wavelength of 365 and 685 nm under zero bias voltage, respectively. This work would provide an additional opportunity for developing multifunctional photodetectors with high performance based o...

A Dual-Band Multilayer InSe Self-Powered Photodetector with High Performance Induced by Surface Plasmon Resonance and Asymmetric Schottky Junction

The current–voltage characteristics of Pd2Si based Schottky diodes on both n‐ and p‐type silicon measured over a wide temperature range (52–295 K) have been interpreted on the basis of thermionic emission‐diffusion mechanism and the assumption of a Gaussian distribution of barrier heights. It is shown that while the occurrence of a distribution of barrier heights is responsible for the apparent decrease of the zero‐bias barrier height (φb0) and nonlinearity in the activation energy plot, the voltage dependence of the standard deviation causes the unusual increase of ideality factor (η) at low temperatures. Also, it is demonstrated that the forward bias shifts the mean barrier height towards the higher side and causes narrowing of the distribution as well. A simple method, involving the use of φb0 vs 1/T data, is suggested to gather evidence for the occurrence of a Gaussian distribution of barrier heights and obtain values of mean barrier height and standard deviation. The experimental results correspond t...

On the existence of a distribution of barrier heights in Pd2Si/Si Schottky diodes

Recent years have witnessed GaN-based devices delivering their promise of unprecedented power and frequency levels and demonstrating their capability as an able replacement for Si-based devices. High-electron-mobility transistors (HEMTs), a key representative architecture of GaN-based devices, are well-suited for high-power and high frequency device applications, owing to highly desirable III-nitride physical properties. However, these devices are still hounded by issues not previously encountered in their more established Siand GaAs-based devices counterparts. Metal–insulator–semiconductor (MIS) structures are usually employed with varying degrees of success in sidestepping the major problematic issues such as excessive leakage current and current instability. While different insulator materials have been applied to GaN-based transistors, the properties of insulator/III-N interfaces are still not fully understood. This is mainly due to the difficulty of characterizing insulator/AlGaN interfaces in a MIS HEMT because of the two resulting interfaces: insulator/AlGaN and AlGaN/GaN, making the potential modulation rather complicated. Although there have been many reports of low interface-trap densities in HEMT MIS capacitors, several papers have incorrectly evaluated their capacitance–voltage (C–V) characteristics. A HEMT MIS structure typically shows a 2-step C–V behavior. However, several groups reported C–V curves without the characteristic step at the forward bias regime, which is likely to the high-density states at the insulator/ AlGaN interface impeding the potential control of the AlGaN surface by the gate bias. In this review paper, first we describe critical issues and problems including leakage current, current collapse and threshold voltage instability in AlGaN/GaN HEMTs. Then we present interface properties, focusing on interface states, of GaN MIS systems using oxides, nitrides and high-κ dielectrics. Next, the properties of a variety of AlGaN/GaN MIS structures as well as different characterization methods, including our own photo-assisted C–V technique, essential for understanding and developing successful surface passivation and interface control schemes, are given in the subsequent section. Finally we highlight the important progress in GaN MIS interfaces that have recently pushed the frontier of nitride-based device technology.

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Insulated gate and surface passivation structures for GaN-based power transistors

I‐V curves of Schottky diodes are simulated for a Gaussian type of the Schottky barrier height (SBH) distribution using the model of noninteracting parallel diodes. The mean value and the standard deviation of the distribution are supposed to be constant, i.e., not dependent on the voltage and the temperature. The influence of the distribution parameters and the temperature on the apparent barrier height and the ideality factor is analyzed. It is shown that the ideality factor increases and the apparent barrier height decreases with increasing standard deviation and decreasing temperature. The simulation also provides a rough estimate for the standard deviation. Values of ∼0.09 V can result in ideality factors up to 1.2. The importance of the effect of series resistance in the approach of noninteracting diodes is emphasized.

Influence of barrier height distribution on the parameters of schottky diodes

Theoretical study of the temperature dependence of electrical characteristics of Schottky diodes with an inverse near-surface layer

We have studied intersecting behaviour of I–V curves measured at different temperatures for inhomogeneous Schottky diodes with a common series resistance. Analytical expression for the voltage where I–T curves have their minima and the existence of which is a necessary condition for the intersection of I–V curves was derived. It is shown that this voltage remains in the low voltage region where I–V curves of Schottky diodes are commonly measured.

Series resistance influence on intersecting behaviour of inhomogeneous Schottky diodes I–V curves

Temperature dependence of barrier height parameters of inhomogeneous Schottky diodes

We have studied current–voltage characteristics of two back-to-back connected Schottky diodes. In many semiconductor devices, we need to prepare one Schottky contact and the second contact should be ohmic. We show that even in the case when the second contact is also of Schottky type but with different barrier height, current–voltage characteristic remains very similar as that of single Schottky diode. The existence of the second Schottky diode with lower-barrier height may not be detectable by inspecting I–V curves of such structure. The analysis and Schottky diode parameter extraction also may not be able to disclose existence of two Schottky contacts in the studied structure. The structure behaves as it would be one single Schottky contact. This knowledge may be used in technology where in many cases the ohmic contact may be substituted by another Schottky contact with lower-barrier height.

J. Osvald

Papers

Influence of barrier height distribution on the parameters of schottky diodes

Theoretical study of the temperature dependence of electrical characteristics of Schottky diodes with an inverse near-surface layer

Series resistance influence on intersecting behaviour of inhomogeneous Schottky diodes I–V curves

Temperature dependence of barrier height parameters of inhomogeneous Schottky diodes

Back‐to‐back connected asymmetric Schottky diodes with series resistance as a single diode