Temperature Sensors Based on AlN/4H-SiC Diodes

2021 ◽  
Vol 13 (7) ◽  
pp. 1318-1323
Author(s):  
Myeong-Cheol Shin ◽  
Dong-Hyeon Kim ◽  
Seong-Woo Jung ◽  
Michael A. Schweitz ◽  
Sang-Mo Koo
Keyword(s):  
Annealing Temperature ◽  
Schottky Diodes ◽  
Forward Bias ◽  
Temperature Sensors ◽  
Electrical Characteristics ◽  
Voltage Range ◽  
Radio Frequency Sputtering ◽  
Sensing Applications ◽  
Current Voltage ◽  
Dc Bias

ABSTRACTThis study report on the formation of AlN/SiC heterostructure Schottky diodes for use of temperature sensing applications enhance the sensitivity. We analyzed the sensitivity of the AlN/SiC Schottky diode sensor depending on the annealing temperature. AlN/4H-SiC Schottky diodes were fabricated by depositing aluminum nitride (AlN) thin film on 4H/SiC by radio frequency sputtering. The forward bias electrical characteristics were determined under DC bias (in the voltage range of 0–1.5 V). The ideality factor, barrier height, and sensitivity were derived through current–voltage–temperature (I–V–T) measurements in the temperature range of 300–500 K. The sensitivity of the AlN/4H-SiC Schottky barrier diode ranged from 2.5–5.0 mV/K.

Metallurgical and Electrical Characteristics of MoAlx Schottky Contacts to n-GaAs

1992 ◽  
Vol 260 ◽  
Author(s):  
T. S. Huang ◽  
J. G. Peng ◽  
C. C. Lin
Keyword(s):  
Thermal Processing ◽  
Annealing Temperature ◽  
Schottky Diodes ◽  
Schottky Contacts ◽  
Electrical Characteristics ◽  
Interfacial Stability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barrier Heights ◽  
Current Voltage

ABSTRACTThe interfacial stability, surface morphology and electrical characteristics of MoAlx contacts to n-GaAs have been investigated by using x-ray diffraction, scanning electron microscopy, sheet resistance and current-voltage measurements. The compositions of rf-cosputtered MoAlx films were x = 0.35, 2.7, and 7.0, respectively. The contacts were annealed by rapid thermal processing in the temperature range 500–1000 °C for 20 s. The interfaces of MoAl0.35/GaAs and MoAl2,7/GaAs were stable up to 900 °C, while the interfaces of MoAl7.0/GaAs were less stable and reactions occurred above 800 °C. The variations of sheet resistances and the barrier heights of the Schottky diodes as a function of annealing temperatures can be well correlated to the interfacial stability. The MoAl2.7/n-GaAs diodes exhibited the best stability and were characterized by the highest barrier height (0.98 V) and nearly unit ideality factor (1.11) after annealing at 900 °C. For all thermally stable MoAlx/n-GaAs Schottky diodes, the barrier heights increased with annealing temperature.

scholarly journals Electrical Properties of Rapidly Annealed Ir and Ir/Au Schottky Contacts on n-Type InGaN

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
V. Rajagopal Reddy ◽  
B. Prasanna Lakshmi ◽  
R. Padma
Keyword(s):  
Barrier Height ◽  
Annealing Temperature ◽  
Schottky Diodes ◽  
Forward Bias ◽  
Interface State ◽  
Schottky Contacts ◽  
Barrier Heights ◽  
Current Voltage ◽  
State Densities ◽  
Optimum Annealing Temperature

The effect of annealing temperature on electrical characteristics of iridium (Ir) and iridium/gold (Ir/Au) Schottky contacts to n-type InGaN have been investigated by means of current-voltage (I-V) and capacitance-voltage (C-V) techniques. It is observed that the barrier height of Ir/n-InGaN and Au/Ir/n-InGaN Schottky diodes increases after annealing at 300∘C for 1 min in N2 ambient compared to the as-deposited. However, the barrier heights are found to be decreased somewhat after annealing at 500∘C for the both Ir and Ir/Au Schottky contacts. From the above observations, it is clear that the optimum annealing temperature for both Ir and Ir/Au Schottky contacts is 300∘C. Moreover, the barrier height (ϕb), ideality factor (n) and series resistance (RS) are determined using Cheung’s and Norde methods. Besides, the energy distribution of interface state densities are determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height. Based on the above results, it is clear that both Ir and Ir/Au Schottky contacts exhibit a kind of thermal stability during annealing.

scholarly journals Низкотемпературный отжиг слаболегированных слоев n-4H-SiC после облучения быстрыми электронами

2019 ◽  
Vol 53 (7) ◽  
pp. 991
Author(s):  
O.M. Корольков ◽  
В.B. Козловский ◽  
A.A. Лебедев ◽  
Н. Слепчук ◽  
J. Toompuu ◽  
...  
Keyword(s):  
Annealing Temperature ◽  
Schottky Diodes ◽  
Electrical Characteristics ◽  
Defect Engineering ◽  
Isochronous Annealing ◽  
Fast Electrons ◽  
Forward Current ◽  
Current Voltage ◽  
Capacitance Voltage ◽  
C 30

AbstractThe effect of low-temperature (up to 600°C) isothermal and isochronous annealing on the electrical characteristics of irradiated n -4 H -SiC JBS Schottky diodes is studied. Irradiation is performed with 0.9-MeV electrons at a dose of 1 × 10^16 cm^–2. It is shown that the forward current–voltage ( I – V ) and capacitance–voltage ( C – V ) characteristics of the irradiated diodes are mainly restored at annealing temperatures of up to 300°C. As the annealing temperature is raised to 500°C, nearly 90% of the defects introduced by irradiation with fast electrons are annealed out. The possible recommended mode of stabilizing annealing to be used in radiation-defect engineering (RDE) is 500°C, 30 min.

scholarly journals Influence of Gas Annealing on Sensitivity of AlN/4H-SiC-Based Temperature Sensors

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 683
Author(s):  
Seung-Woo Jung ◽  
Myeong-Cheol Shin ◽  
Michael A. Schweitz ◽  
Jong-Min Oh ◽  
Sang-Mo Koo
Keyword(s):  
Thin Film ◽  
Photoelectron Spectroscopy ◽  
Temperature Sensor ◽  
Temperature Sensors ◽  
Electrical Characteristics ◽  
X Ray ◽  
Radio Frequency Sputtering ◽  
Current Voltage ◽  
Before And After ◽  
A Current

In this study, the physical and electrical characteristics of an AlN/4H-SiC Schottky barrier diode-based temperature sensor annealed in various gas atmospheres were investigated. An aluminum nitride (AlN) thin film was deposited on a 4H-SiC substrate via radio-frequency sputtering followed by annealing in N2 or O2 gas. The chemical composition of the film was determined by X-ray photoelectron spectroscopy (XPS) before and after annealing, and its electrical properties were evaluated by plotting a current–voltage (I–V) curve. The voltage–temperature (V–T) characteristics of the sensor were extracted from the current–voltage–temperature (I–V–T) plots constructed in the temperature range between 475 and 300 K in steps of 25 K. Sensitivities of 9.77, 9.37, and 2.16 mV/K were obtained for the as-grown, N2-annealed, and O2-annealed samples, respectively.

Impact of Interface Traps on Current-Voltage Characteristics of 4H-SiC Schottky-Barrier Diodes

2014 ◽  
Vol 778-780 ◽  
pp. 710-713 ◽  
Author(s):  
Hamid Amini Moghadam ◽  
Sima Dimitrijev ◽  
Ji Sheng Han
Keyword(s):  
Schottky Barrier ◽  
Schottky Barrier Height ◽  
Schottky Diodes ◽  
Forward Bias ◽  
Interface Traps ◽  
Barrier Heights ◽  
Current Voltage ◽  
Donor Type ◽  
Current Voltage Characteristics ◽  
Expected Values

This paper presents a physical model based on interface traps to explain both the larger barrier heights of practical Schottky diodes in comparison to the theoretically expected values and the appearance of a knee in the log I–V characteristics. According to this model, acceptor-type interface traps near the valance band increase the Schottky barrier height, which shifts the log I–V characteristic to higher forward-bias voltages. In addition to the acceptor traps, donor-type interface traps can appear near the conduction band, and when they do, they cause the knee in the log I–V characteristics as their energy level falls below the Fermi level and the charge associated with these traps changes from positive to neutral.

ELECTRICAL RESISTANCE OF CRACK-FREE GaN/AlN HETEROSTRUCTURE GROWN ON Si(111)

2008 ◽  
Vol 17 (03) ◽  
pp. 299-304 ◽  
Author(s):  
L. S. CHUAH ◽  
Z. HASSAN ◽  
H. ABU HASSAN
Keyword(s):  
Electrical Resistance ◽  
Intermediate Layer ◽  
Forward Bias ◽  
Differential Resistance ◽  
Back Surface ◽  
Effusion Cell ◽  
Si Substrate ◽  
Voltage Range ◽  
Current Voltage ◽  
Current Flows

This paper presents the electrical resistance of crack-free n-GaN/AlN/n-Si(111) diodes in relation to the temperature of the Al effusion cell for the growth of AlN intermediate layer (348 nm thickness) using radio-frequency molecular beam epitaxy (RF-MBE). The thickness of the unintentionally doped n-type GaN thin film is in the range of 63–100 nm. Aluminium (300 nm thickness) was sputtered onto the n-type GaN through a metal mask, followed by the 100 nm thick titanium (Ti) capping layer to obtain an ohmic contact. The back contact was created on the back surface of the Si substrate by evaporating indium (In) followed by thermal annealing at 400°C. We will consider the above as a device on an n-type Si(111) substrate, where the electron current flows from the Si substrate to the n-type GaN top layer. It was found that the current–voltage (I–V) characteristics depend on the various deposition temperature of the Al effusion cell for the growth of the AlN intermediate layer. In the forward bias region, where the electrons flow from Si(111) to the GaN top layer, we observe a threshold voltage of approximately 0.5 V for turning on a high current. The order of differential resistance magnitude was nearly a constant in the voltage range of 1.0 to 3.0 V.

Electronic Device Fabricated From Polyaniline / Single walled Carbon Nanotubes Composite

2003 ◽  
Vol 772 ◽  
Author(s):  
P.C. Ramamurthy ◽  
A.M. Malshe ◽  
W.R. Harrell ◽  
R.V. Gregory ◽  
K. McGuire ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Device ◽  
Electronic Devices ◽  
Single Walled Carbon Nanotubes ◽  
Electrical Characteristics ◽  
Voltage Range ◽  
Single Walled Carbon ◽  
Current Voltage ◽  
Walled Carbon Nanotubes ◽  
Limited Conduction

AbstractComposites of high molecular weight polyaniline and single walled carbon nanotubes are investigated for applications to electronic devices. Electrical characteristics of devices fabricated using this composite show an order magnitude higher current level than those measured in the neat polyaniline devices. Composite materials and devices with various weight percentages of single walled carbon nanotubes were also fabricated. Current-voltage (I-V) characteristics of these devices indicate a significant increase in current with an increase in carbon nanotube concentration in the composite. Analysis of the forward I-V characteristics of these composite devices on a log-log scale shows two power law regions. In the lower voltage range, the exponent is 1, which is consistent with ohmic conduction, while in the higher voltage range, the exponent is between 1.1 and 1.5, which is consistent with space-charge-limited conduction.

Influence of metal thickness to sensitivity of Pt/GaN Schottky diodes for gas sensing applications

2003 ◽  
Vol 798 ◽  
Author(s):  
V. Tilak ◽  
M. Ali ◽  
V. Cimalla ◽  
V. Manivannan ◽  
P. Sandvik ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Schottky Diodes ◽  
Forward Bias ◽  
Current Mode ◽  
Hydrogen Gas ◽  
Constant Current ◽  
Sensing Applications ◽  
Metal Thickness ◽  
Hydrogen Gas Sensors ◽  
Si Doped

ABSTRACTHydrogen gas sensors based on Pt/GaN Schottky diode structures were fabricated and their responses to hydrogen were studied. These diodes were fabricated on Si doped GaN layer (ND = 1×1017). Three sets of diodes were fabricated with 80 Å, 240 Å and 400 Å of Pt for the Schottky contacts. The electronic performances of 0.25 × 0.25 mm devices were tested in up to 1 % H2 gas in synthetic air (79% N2, 21% O2) by volume. The devices were operated in constant current mode in a forward bias condition. The change in voltage was monitored with the diodes exposed to hydrogen and to dry air at varying temperatures. The responses increased as the thickness of the Schottky metal contact decreased at any given temperature up to 310 °C. The trend of increasing response with decreasing thickness was also observed in 0.5 × 0.5 mm and 1.0 × 1.0 mm size Schottky diodes. SEM studies of the microstructure showed that the thinner Pt devices had higher grain boundary densities. The increase in sensitivity with decreasing thickness points to the dissociation of molecular hydrogen on the surface, the diffusion of atomic hydrogen through the Pt grain boundaries and the adsorption of hydrogen to the surface as a possible mechanism of sensing of hydrogen by Schottky diodes.

Influence of annealing temperature on the electrical, structural and surface morphology properties of Au/Cr Schottky contacts on n-type InP

2014 ◽  
Vol 5 (3) ◽  
pp. 823-836 ◽  
Author(s):  
Bhaskar Reddy M
Keyword(s):  
Surface Morphology ◽  
Schottky Diode ◽  
Ideality Factor ◽  
Annealing Temperature ◽  
Forward Bias ◽  
Interface State ◽  
State Density ◽  
Schottky Contacts ◽  
Current Voltage ◽  
Optimum Annealing Temperature

The influence of rapid thermal annealing on the electrical and structural properties of Au/Cr/n-InP Schottky diode havebeen investigated by the current-voltage (I-V), capacitance-voltage (C-V), auger electron spectroscopy (AES) and X-raydiffraction (XRD) measurements. The Schottky barrier height (SBH) and ideality factor (n) of the as-deposited Au/Cr/n-InPSchottky diode are 0.51 eV (I-V)/0.64 eV (C-V) and 1.81, respectively. When the contact is annealed at 200 oC in N2atmosphere for 1min, a maximum SBH (0.71 eV (I-V)/0.81 eV (C-V)) and low ideality factor (1.15) are achieved for theAu/Cr/n-InP Schottky diode. However, after annealing at 300 oC, the SBH slightly decreases to 0.58 eV (I-V)/0.69 eV (CV),and ideality factor increases to 1.45, respectively. The SBHs obtained from the Norde and Cheung’s methods areclosely matched with those obtained from the I-V method. Results show that the optimum annealing temperature for theAu/Cr/n-InP Schottky diode is 200 °C. Further, the discrepancy between SBHs calculated from I-V and C-V methods isalso discussed. Moreover, the energy distribution of interface state density is estimated from forward bias I-Vcharacteristics at different annealing temperatures. AES and XRD studies reveal that the formation of indium (In) phasesat Au/Cr and InP interface may be the cause for the increase in SBH after annealing at 200 oC. The AFM results show thatthe overall surface morphology of Au/Cr Schottky contacts is considerably smooth at elevated tempratures.

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