Evidence of thermionic emission in forward biased β-Ga2O3 Schottky diodes at Boltzmann doping limit

Specific on-resistance Ron estimated from current density-voltage characteristics of Schottky diodes on thick layers exhibits variations from tens of mW.cm2 to tens of W.cm2 for different doping levels. In order to understand the occurrence of high on-state resistance, Schottky barrier heights were first estimated for both forward and reverse bias with the application of thermionic emission theory and were in agreement with a literature reported values. Decrease in mobility with the temperature was observed and its dependencies of T–1.3 and T–2.0 for moderately doped and low doped samples respectively were estimated. From deep level measurements by Minority Carrier Transient Spectroscopy, an influence of shallow boron related levels and D-center on dependence of on-state resistance was observed, being more pronounced in low doped samples. Similar tendency was observed in depth profiling of Ron. This suggests a major role of boron in a compensation mechanism thus resulting in high Ron.

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Effects of Very High Workfunction Metals or Metal Alloys (NiCr) on High Switching Speed, HV Schottky Diodes for Mixed Signal or RF ASIC

MRS Advances ◽

10.1557/adv.2020.336 ◽

2020 ◽

Vol 5 (37-38) ◽

pp. 1937-1946

Author(s):

J. Pan ◽

A. Gaibrois ◽

M. Marripelly ◽

J. Leung ◽

S. Suko ◽

...

Keyword(s):

Work Function ◽

Schottky Diodes ◽

Thermionic Emission ◽

Metal Alloys ◽

Forward Voltage ◽

Switching Speed ◽

External Bias ◽

High Switching Speed ◽

High Work ◽

Very High

AbstractFor high switching speed HV Schottky diodes, with very high work function metal and extremely lightly doped epi, the built-in potential may be too high for thermionic emission to occur, when the applied external voltage is quite low (near VF = 0.07V). If the epi is lightly doped p type, the built-in potential (VBuilt-in: potential difference between the metal and silicon Fermi levels) is 1.0V (measured with CV). If the external bias is 0.1V, near the measured VF, it is not enough to overcome the built-in potential for thermionic emission as illustrated. It is likely that in addition to thermionic emission, tunnelling and diffusion currents also contribute to the total HV Schottky diode forward current. TCAD simulation of HV Schottky diodes with N+ guard bands suggests the potential barrier and electric fields at the Schottky junction are relatively high for thermionic emission to occur, when external bias V ≈ VF. In this paper we report HV Schottky diodes fabricated with various metals, metal alloys and epitaxial films. Metal work functions and epi doping profiles are extracted with high frequency Capacitance-Voltage (CV) technique. 150V of breakdown voltage and very low forward voltage (VF = 0.07V) are demonstrated. The measured data indicate very high work function metal or metal alloy is needed to achieve high switching speed and low forward voltage.

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THE EFFECT OF ETCHING TIME ON RECTIFYING CHARACTERISTIC IN SnO2/p-Si AND SnO2/p-PoSi HETEROJUNCTION SCHOTTKY DIODES

Modern Physics Letters B ◽

10.1142/s0217984913500516 ◽

2013 ◽

Vol 27 (08) ◽

pp. 1350051 ◽

Cited By ~ 1

Author(s):

ALIREZA BIARAM ◽

HOSEIN ESHGHI

Keyword(s):

Data Analysis ◽

Series Resistance ◽

Schottky Diodes ◽

Thermionic Emission ◽

Etching Time ◽

Spray Pyrolysis Method ◽

Porous Si ◽

Si Substrates ◽

Pyrolysis Method ◽

Heterojunction Diodes

We have fabricated SnO 2/p- Si and SnO 2/p- PoSi heterojunction diodes by spray pyrolysis method. To prepare porous Si substrates, the etching time was varied from 10 to 20 and 30 mins. In these samples, the SEM micrographs showed a distributed pore areas surrounded by columnar walls with various height. The data analysis of the rectified I–V characteristic, using thermionic emission Schottky diode theory, showed that although the barrier height is about 0.5–0.6 eV in all samples other two important diode parameters, i.e. the ideality factor n and the series resistance rs, are strongly etching time-dependant and are increased with increasing the etching time.

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A Study of Inhomogeneous Schottky Diodes on n-Type 4H-SiC

Materials Science Forum ◽

10.4028/www.scientific.net/msf.527-529.911 ◽

2006 ◽

Vol 527-529 ◽

pp. 911-914 ◽

Cited By ~ 1

Author(s):

D.J. Ewing ◽

Qamar-ul Wahab ◽

Sergey P. Tumakha ◽

Leonard J. Brillson ◽

X.Y. Ma ◽

...

Keyword(s):

Low Voltage ◽

Deep Level ◽

Schottky Diodes ◽

Forward Bias ◽

Polarized Light ◽

Thermionic Emission ◽

Chemical Vapor ◽

Double Barrier ◽

X Ray ◽

Sic Wafer

In this study, we performed a statistical analysis of 500 Ni Schottky diodes distributed across a 2-inch, n-type 4H-SiC wafer with an epilayer grown by chemical vapor deposition. A majority of the diodes displayed ideal thermionic emission when under forward bias, whereas some diodes showed ‘double-barrier’ characteristics with a ‘knee’ in the low-voltage log I vs. V plot. X-ray topography (XRT) and polarized light microscopy (PLM) revealed no correlations between screw dislocations and micropipes and the presence of double-barrier diodes. Depth resolved cathodoluminescence (DRCLS) indicated that certain deep-level states are associated with the observed electrical variations.

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Equivalent Circuit Model of Semiconductor Nanowire Diode by SPICE

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2007.18083 ◽

2007 ◽

Vol 7 (11) ◽

pp. 4089-4093

Author(s):

Sehan Lee ◽

Yunseop Yu ◽

Sungwoo Hwang ◽

Doyeol Ahn

Keyword(s):

Equivalent Circuit ◽

Schottky Diode ◽

Schottky Diodes ◽

Equivalent Circuit Model ◽

Thermionic Emission ◽

Metal Structure ◽

Circuit Model ◽

Semiconductor Nanowire ◽

Circuit Simulator ◽

Thermionic Field Emission

An equivalent circuit model of nanowire diodes is introduced. Because nanowire diodes inevitably involve a metal-semiconductor-metal structure, they consist of two metal-semiconductor contacts and one resistor in between these contacts. Our equivalent circuit consists of two Schottky diodes and one resistor. The current through the reverse-biased Schottky diode is calculated from the thermionic field emission (TFE) theory and that of the forward-biased Schottky diode is obtained from the classical thermionic emission (TE) equation. Our model is integrated into the conventional circuit simulator SPICE by a sub-circuit with TFE and TE routines. The results simulated with our model by SPICE are in good agreement with various, previously reported experimental results.

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.510-511.265 ◽

2012 ◽

Vol 510-511 ◽

pp. 265-270 ◽

Cited By ~ 3

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.

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High-Temperature Reliability Analysis of 1200V/100A 4H-SiC Junction Barrier Schottky Diodes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1004.1004 ◽

2020 ◽

Vol 1004 ◽

pp. 1004-1009

Author(s):

Yi Dan Tang ◽

Xin Yu Liu ◽

Cheng Zhan Li ◽

Yun Bai ◽

Hong Chen ◽

...

Keyword(s):

High Temperature ◽

Reliability Analysis ◽

Stress Test ◽

Schottky Diodes ◽

Thermionic Emission ◽

Image Force ◽

Data Consistency ◽

Current Characteristics ◽

The Stability ◽

The One

The high-temperature (up to 200 °C) reliability analysis of 1200V/100A 4H-SiC JBS under 168 hours of high-temperature storage stress (HTSS), high-temperature reverse bias (HTRB) and high-humidity HTRB (H3TRB) stress test are reported. Results show that, all the statistical distribution of the data consistency is more dispersed after HTSS, HTRB and H3TRB test, which suggests that there are more degradation in the forward voltage and leakage current characteristics of JBS device under high temperature (up to 423K) stress. The increased reverse leakage currents after HTSS and HTRB stresses at different test temperatures are mainly due to the thermionic emission with the image force barrier height lowering. However, it is not the same phenomenon after HTRB stress. And the stability of VR under HTRB test is better than the one under HTSS test, which may be due to the migration and accumulation of charge during exposure to HTRB.

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A New Approach to Temperature Dependent Ideality Factors in Schottky Contacts

MRS Proceedings ◽

10.1557/proc-260-359 ◽

1992 ◽

Vol 260 ◽

Cited By ~ 13

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.

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Equivalent Circuit Model of Semiconductor Nanowire Diode by SPICE

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2007.012 ◽

2007 ◽

Vol 7 (11) ◽

pp. 4089-4093 ◽

Cited By ~ 13

Author(s):

Sehan Lee ◽

Yunseop Yu ◽

Sungwoo Hwang ◽

Doyeol Ahn

Keyword(s):

Equivalent Circuit ◽

Schottky Diode ◽

Schottky Diodes ◽

Equivalent Circuit Model ◽

Thermionic Emission ◽

Metal Structure ◽

Circuit Model ◽

Semiconductor Nanowire ◽

Circuit Simulator ◽

Thermionic Field Emission

An equivalent circuit model of nanowire diodes is introduced. Because nanowire diodes inevitably involve a metal-semiconductor-metal structure, they consist of two metal-semiconductor contacts and one resistor in between these contacts. Our equivalent circuit consists of two Schottky diodes and one resistor. The current through the reverse-biased Schottky diode is calculated from the thermionic field emission (TFE) theory and that of the forward-biased Schottky diode is obtained from the classical thermionic emission (TE) equation. Our model is integrated into the conventional circuit simulator SPICE by a sub-circuit with TFE and TE routines. The results simulated with our model by SPICE are in good agreement with various, previously reported experimental results.

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Evaluation of Correct Value of Richardson's Constant by Analyzing the Electrical Behavior of Three Different Diodes at Different Temperatures

Materials Science Forum ◽

10.4028/www.scientific.net/msf.711.174 ◽

2012 ◽

Vol 711 ◽

pp. 174-178 ◽

Cited By ~ 4

Author(s):

Muhammad Yousuf Zaman ◽

Denis Perrone ◽

Sergio Ferrero ◽

Luciano Scaltrito ◽

Marco Naretto

Keyword(s):

Silicon Carbide ◽

Schottky Diode ◽

Schottky Diodes ◽

Thermionic Emission ◽

Effective Area ◽

Large Area ◽

Current Voltage ◽

Different Temperatures ◽

Barrier Inhomogeneities ◽

Electrical Characterizations

Various attempts have been made to evaluate the correct value (A*=146 A/cm2.K2) ofRichardson's constant. In 2005 S. Ferrero et al. published their research in which they performedan analysis of electrical characterizations of twenty Ti/4H-SiC(titanium on silicon carbide) Schottkydiodes with the help of thermionic emission theory and evaluated the value of Richardson's constantto be 17±8 A/cm2.K2; which is very low as compared to the theoretical value of 146 A/cm2.K2.Wehave tried in this paper to evaluate the Richardson's constant's value by nearly same experimental tech-niques followed by S. Ferrero et al. and additionally, have applied Tung's theoretical approach whichdeals with the incorrect value of A* in the perspective of Schottky barrier inhomogeneities caused bythe presence of nanometer size low barrier patches present in the uniform high barrier of the Schottkydiode.We have fabricated two Ti/4H-SiC (titanium on silicon carbide) Schottky diodes with differentareas and oneMo/4H-SiC (molybdenumon silicon carbide) Schottky diode. In this paper we have pre-sented a comparative analysis of forward current-voltage characteristics of all three Schottky diodes.In all three cases we were successful in the evaluation of nearly correct value of Richardson's constant.This work emphasizes the effects of differentmetal-SiC combinations and laboratory environments onthe evaluation of Richardson's constant and the effective area involved in the current transport. As pre-dicted by Tung's model the effective area is seen to be substantially different from the geometric areaof the Schottky diode. Evaluated values of A*, with an error of ±2, come out to be 145.39, 148.33and 148.33 A/cm2.K2for Ti/4H-SiC(large area), Mo/4H-SiC and Ti/4H-SiC(small area) Schottkydiodes, respectively.

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