Barrier properties and current conduction mechanism for metal contacts to lightly and highly doped p-type 4H-SiC

2021 ◽  
Author(s):  
Lingqin Huang ◽  
Yue Ma ◽  
Sumin Pan ◽  
Jing Zhu ◽  
Xiaogang Gu
Keyword(s):  
Carrier Transport ◽  
Theoretical Calculations ◽  
Thermionic Emission ◽  
Barrier Properties ◽  
Emission Model ◽  
Metal Contacts ◽  
Barrier Heights ◽  
Thermionic Field Emission ◽  
Barrier Inhomogeneities ◽  
P Type

Abstract The barrier properties of Ti, Ni and Pt contact to lightly (9×1016 cm-3) and highly (9×1018 cm-3) doped p-type 4H-SiC were investigated. It is found that the barrier heights and ideality factors estimated from thermionic emission model for the lightly doped samples are non-ideal and abnormally temperature dependent. The anomalies have been successfully explained in terms of both pinch-off model and Gaussian distribution of inhomogeneous barrier heights. In addition, the evaluated homogeneous barrier heights are reasonably close to the average barrier heights from capacitance-voltage measurements. For the highly doped samples, thermionic field emission (TFE) is found to be the dominant carrier transport mechanism. The barrier heights estimated from TFE model are temperature independent. If the barrier inhomogeneities and tunneling effects are considered, the experimental results of the samples are in well agreement with the theoretical calculations.

Rectifying and Schottky characteristics of a-SixGe1−xOy with metal contacts

2014 ◽  
Vol 92 (7/8) ◽  
pp. 606-610 ◽  
Author(s):  
Md Muztoba ◽  
Mukti Rana
Keyword(s):  
Ohmic Contact ◽  
Infrared Detector ◽  
Schottky Contact ◽  
Thermionic Emission ◽  
Emission Model ◽  
Metal Contacts ◽  
Temperature Changes ◽  
Barrier Heights ◽  
Current Voltage ◽  
Semiconductor Contacts

Metal–semiconductor contacts are a vital part of semiconductor devices as they can form a Schottky barrier or an Ohmic contact. The nature of the contact plays an important role in determining the electrical and physical characteristics of the device and hence is of paramount importance in the operation of the device. In the current work we report the design, fabrication, and current–voltage (I-V) characteristics of microbolometers, a type of infrared detector where the change in temperature changes the resistance of the sensing layer. Eight different types of microbolometers were fabricated using a-SixGe1−x or a-SixGe1−xOy sensing layers and Ti, Cr, Al, Au, Ni, or Ni0.80Cr0.20 metals contacts. It has been observed that bolometers with an a-Si0.15Ge0.85 (Si was lightly p-doped) sensing layer formed a Schottky contact with Ti, Au, Cr, and Al contact metals, while bolometers with a-Si0.15Ge0.85 (Si was heavily n-doped) sensing layers formed an Ohmic contact with Au. For microbolometers with a Si0.15Ge0.85O0.039 sensing layer, both Ni and Ni0.80Cr0.20 contact metals formed the Ohmic contact. For a-SixGe1−x and a-SixGe1−xOy microbolometers, Au and Ni0.80Cr0.20 were used as the absorber layers, respectively. The I–V characteristics of the microbolometers were analyzed with a thermionic emission model. A linear dependence on the Ge composition was approximated to find the effective Richardson constant. The theory predicts Richardson constants of 112 and 50 A/cm2K2 for Si and Ge, respectively. Barrier heights of all devices are calculated and the reasons for the formation of the Ohmic and Schottky contacts are discussed.

Investigation of carrier transport mechanisms in the Cu–Zn–Se based hetero-structure grown by sputtering technique

2018 ◽  
Vol 96 (7) ◽  
pp. 816-825 ◽  
Author(s):  
H.H. Güllü ◽  
M. Terlemezoğlu ◽  
Ö. Bayraklı ◽  
D.E. Yıldız ◽  
M. Parlak
Keyword(s):  
Barrier Height ◽  
Carrier Transport ◽  
Thermionic Emission ◽  
Electrical Characterization ◽  
Band Gap Energy ◽  
Zero Bias ◽  
Hetero Structure ◽  
Current Voltage ◽  
P Type

In this paper, we present results of the electrical characterization of n-Si/p-Cu–Zn–Se hetero-structure. Sputtered film was found in Se-rich behavior with tetragonal polycrystalline nature along with (112) preferred orientation. The band gap energy for direct optical transitions was obtained as 2.65 eV. The results of the conductivity measurements indicated p-type behavior and carrier transport mechanism was modelled according to thermionic emission theory. Detailed electrical characterization of this structure was carried out with the help of temperature-dependent current–voltage measurements in the temperature range of 220–360 K, room temperature, and frequency-dependent capacitance–voltage and conductance-voltage measurements. The anomaly in current–voltage characteristics was related to barrier height inhomogeneity at the interface and modified by the assumption of Gaussian distribution of barrier height, in which mean barrier height and standard deviation at zero bias were found as 2.11 and 0.24 eV, respectively. Moreover, Richardson constant value was determined as 141.95 Acm−2K−2 by means of modified Richardson plot.

Metal/Semiconductor Contacts to Silicon Carbide: Physics and Technology

2018 ◽  
Vol 924 ◽  
pp. 339-344 ◽  
Author(s):  
Fabrizio Roccaforte ◽  
Marilena Vivona ◽  
Giuseppe Greco ◽  
Raffaella Lo Nigro ◽  
Filippo Giannazzo ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Carrier Transport ◽  
Transport Mechanisms ◽  
Metal Contacts ◽  
Semiconductor Interfaces ◽  
Key Points ◽  
Schottky Type ◽  
Semiconductor Contacts ◽  
P Type

The physics and technology of metal/semiconductor interfaces are key-points in the development of silicon carbide (SiC) based devices. Although in the last decade, the metal to 4H-SiC contacts, either Ohmic or Schottky type, have been extensively investigated with important achievements, these remain even now an intriguing topic since metal contacts are fundamental bricks of all electronic devices. Hence, their comprehension is at the base of the improvement of the performances of simple devices and complex systems. In this context, this paper aims to highlight some relevant aspects related to metal/semiconductor contacts to SiC, both on n-type and p-type, with an emphasis on the role of the barrier and on the carrier transport mechanisms at the interfaces.

TEMPERATURE DEPENDENCE OF ELECTRICAL CHARACTERISTICS OF Cr/p–Si(100) SCHOTTKY BARRIER DIODES

2008 ◽  
Vol 22 (14) ◽  
pp. 2309-2319 ◽  
Author(s):  
K. ERTURK ◽  
M. C. HACIISMAILOGLU ◽  
Y. BEKTORE ◽  
M. AHMETOGLU
Keyword(s):  
Temperature Dependence ◽  
Schottky Barrier ◽  
Barrier Height ◽  
Thermionic Emission ◽  
Electrical Characteristics ◽  
Schottky Barrier Diodes ◽  
Semiconductor Interface ◽  
Linear Portion ◽  
Barrier Heights ◽  
P Type

The electrical characteristics of Cr / p – Si (100) Schottky barrier diodes have been measured in the temperature range of 100–300 K. The I-V analysis based on thermionic emission (TE) theory has revealed an abnormal decrease of apparent barrier height and increase of ideality factor at low temperature. The conventional Richardson plot exhibits non-linearity below 200 K with the linear portion corresponding to activation energy 0.304 eV and Richardson constant (A*) value of 5.41×10-3 Acm-2 K -2 is determined from the intercept at the ordinate of this experimental plot, which is much lower than the known value of 32 Acm-2 K -2 for p-type Si . It is demonstrated that these anomalies result due to the barrier height inhomogeneities prevailing at the metal-semiconductor interface. Hence, it has been concluded that the temperature dependence of the I-V characteristics of the Cr/p – Si Schottky barrier diode can be successfully explained on the basis of TE mechanism with a Gaussian distribution of the barrier heights. Furthermore, the value of the Richardson constant found is much closer than that obtained without considering the inhomogeneous barrier heights.

Comparative Study of Temperature Dependent Barrier Heights of Pd/ZnO Schottky Diodes Grown along Zn- and O-Faces

2012 ◽  
Vol 510-511 ◽  
pp. 265-270 ◽  
Author(s):  
M. Asghar ◽  
Khalid Mahmood ◽  
Adnan Ali ◽  
M.A. Hasan
Keyword(s):  
Barrier Height ◽  
Deep Level ◽  
Schottky Diodes ◽  
Thermionic Emission ◽  
Growth Conditions ◽  
Distribution Model ◽  
Metal Contacts ◽  
Temperature Dependent ◽  
Barrier Heights ◽  
Two Samples

In this study, the effect of polar face on Schottky barrier diodes has been investigated. Two samples of ZnO were grown hydrothermally under similar growth conditions. The Palladium (Pd) metal contacts of area 0.78 mm2were fabricated on both faces and were studied comprehensively using DLS-83 Deep Level Spectrometer over temperature range of 160K330K. The current-voltage (IV) measurements revealed that the ideality factor n and barrier height ϕBwere strongly temperature dependent for both faces (Zn and O-face) of ZnO, indicating that the thermionic emission is not the dominant process, which showed the inhomogenity in the barrier heights of grown samples. This barrier height inhomogenity was explained by applying Gaussian distribution model. The extrapolation of the linear ϕapverses n plot to n = 1 has given a homogeneous barrier height of approximately 0.88±0.01 eV and 0.76±0.01 eV for Zn and O-faces respectively. ϕapversus 1/T plot was drawn to obtain the values of mean barrier height for Zn and O-face (0.88±0.01 eV, 0.76±0.01 eV) and standard deviation (δs) (0.015±0.001 V, 0.014±0.001 V) at zero bais respectively. The value of δsfor the Zn-face is larger than O-face, showing that inhomogenity in the barrier heights is more in the sample grown along Zn-face as compared to the sample grown along O-face.

Room temperature I–V and C–V characteristics of Au/mTPP/p-Si organic MIS devices

2018 ◽  
Vol 82 (2) ◽  
pp. 20101
Author(s):  
Şadan Özden ◽  
Ömer Güllü ◽  
Osman Pakma
Keyword(s):  
Room Temperature ◽  
Thermionic Emission ◽  
Electrical Characteristics ◽  
Trap States ◽  
Barrier Heights ◽  
Coating Method ◽  
Barrier Inhomogeneities ◽  
Rectification Coefficient ◽  
Mis Devices ◽  
Resistance Value

The room temperature electrical characteristics of the organic Au/mTPP/p-Si device fabricated by spin coating method were investigated with I–V and C–V measurements. It has been determined that the device has a high rectification coefficient and current transport is dominated by the thermionic emission. The serial resistance value is calculated at 92 ohms with two different approaches. Serial resistance effects were also found to be effective in C–V and G–V measurements. The different barrier heights from the I–V and C–V measurements indicate possible interface and trap states or barrier inhomogeneities.

A New Approach to Temperature Dependent Ideality Factors in Schottky Contacts

1992 ◽  
Vol 260 ◽  
Author(s):  
Zs. J. Horváth
Keyword(s):  
Experimental Data ◽  
Low Temperatures ◽  
Schottky Diodes ◽  
Thermionic Emission ◽  
Schottky Contacts ◽  
Temperature Dependent ◽  
Model Calculations ◽  
New Approach ◽  
Barrier Heights ◽  
Thermionic Field Emission

ABSTRACTSchottky diodes often exhibit anomalous current-vol tage characteristics at low temperatures (T) with T dependent ideality factors (IF) and apparent barrier heights (BH) evaluated for the thermionic emission. In this paper theoretical expressions are first presented for the T dependences of the IF and the apparent BH for the thermionic-field emission (TFE) including the bias dependence of BH. Model calculations are reported, which has been performed using these expressions, and their results are compared with the available experimental data. It is shown that the T dependence of the 1 Fs and apparent BHs often may be explained self consistently by the TFE with anomalously high characteristic energies Eoo.

Barrier heights and Fermi level pinning in metal contacts on p-type GaN

2020 ◽  
Vol 116 (21) ◽  
pp. 213506 ◽  
Author(s):  
Sumaiya Wahid ◽  
Nadim Chowdhury ◽  
Md Kawsar Alam ◽  
Tomás Palacios
Keyword(s):  
Fermi Level ◽  
Metal Contacts ◽  
Fermi Level Pinning ◽  
Barrier Heights ◽  
P Type

Temperature Dependent Study of Carrier Diffusion in Photon Enhanced Thermionic Emission Solar Converters

2013 ◽  
Vol 772 ◽  
pp. 634-639
Author(s):  
Yang Yang ◽  
Wen Zheng Yang ◽  
Wei Dong Tang ◽  
Chuan Dong Sun
Keyword(s):  
Solar Energy ◽  
Temperature Dependence ◽  
Carrier Transport ◽  
Elevated Temperatures ◽  
Thermionic Emission ◽  
Back Surface ◽  
Optical Parameters ◽  
Material Parameters ◽  
Novel Concept ◽  
P Type

Photon Enhanced Thermionic Emission (PETE) is a novel concept in solar energy conversion, which can efficiently harvest solar energy at elevated temperatures. However, the temperature dependence of material parameters has not been clearly stated so far. In this study, a model for carrier transport is presented based on one dimension diffusion equation. Material data of GaAs are used to testify the temperature impact on material parameters. We find that for higher doped p-type GaAs which is suitable for PETE cathode material, its electron diffusion length shows weak temperature dependence. Carrier transport efficiency can be boosted by optimizing the geometry of the cathode and the optical parameters of the material. Finally, we propose a design of reflective mode cathode with reflective back surface and nanostructure emissive surface for PETE application.

Mechanism of Carrier Transport in n-Type β-FeSi2/Intrinsic Si/p-Type Si Heterojunctions

2015 ◽  
Vol 1119 ◽  
pp. 189-193
Author(s):  
Nathaporn Promros ◽  
Motoki Takahara ◽  
Ryuji Baba ◽  
Tarek M. Mostafa ◽  
Mahmoud Shaban ◽  
...  
Keyword(s):  
Ideality Factor ◽  
Carrier Transport ◽  
Linear Part ◽  
Forward Bias ◽  
Thermionic Emission ◽  
Forward Bias Voltage ◽  
Space Charge Limit ◽  
Current Voltage ◽  
P Type ◽  
Direct Current Sputtering

Preparation of n-type β-FeSi2/intrinsic Si/p-type Si heterojunctions was accomplished by facing-target direct-current sputtering (FTDCS) and measuring their current-voltage characteristic curves at low temperatures ranging from 300 K down to 50 K. A mechanism of carrier transport in the fabricated heterojunctions was investigated based on thermionic emission theory. According to this theory, the ideality factor was calculated from the slope of the linear part of the forward lnJ-V plot. The ideality factor was 1.12 at 300 K and increased to 1.99 at 225 K. The estimated ideality factor implied that a recombination process was the predominant mechanism of carrier transport. When the temperatures decreased below 225 K, the ideality factor was estimated to be higher than two and parameter A was estimated to be constant. The obtained results implied that the mechanism of carrier transport was governed by a trap-assisted multi-step tunneling process. At high forward bias voltage, the predominant mechanism of carrier transport was changed into a space charge limit current process.

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