High Voltage Silicon Carbide Schottky Diodes with Single Zone Junction Termination Extension

High voltage 4H-SiC Schottky diodes with single-zone junction termination extension (JTE) have been fabricated and characterised. Commercial 4H-SiC epitaxial wafers with 10, 20 and 45 +m thick n layers (with donor concentrations of 3×1015, 8×1014 and 8×1014 cm-3, respectively) were used. Boron implants annealed under argon flow at 1500°C for 30 minutes, without any additional protection of the SiC surface, were used to form JTE’s. After annealing, the total charge in the JTE was tuned by reactive ion etching. Diodes with molybdenum Schottky contacts exhibited maximum reverse voltages of 1.45, 3.3 and 6.7 kV, representing more than 80% of the ideal avalanche breakdown voltages and corresponding to a maximum parallel-plane electric field of 1.8 MV/cm. Diodes with a contact size of 1×1 mm were formed on 10 +m thick layers (production grade) using the same device processing. Characterisation of the diodes across a quarter of a 2-inch wafer gave an average value of 1.21 eV for barrier heights and 1.18 for ideality factors. The diodes exhibited blocking voltages (defined as the maximum voltage at which reverse current does not exceed 0.1 mA) higher than 1 kV with a yield of 21 %.

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Evaluation of On-State Resistance and Boron-Related Levels in n-Type 4H-SiC

Materials Science Forum ◽

10.4028/www.scientific.net/msf.483-485.425 ◽

2005 ◽

Vol 483-485 ◽

pp. 425-428 ◽

Cited By ~ 2

Author(s):

R.R Ciechonski ◽

Samuele Porro ◽

Mikael Syväjärvi ◽

Rositza Yakimova

Keyword(s):

Minority Carrier ◽

Deep Level ◽

Schottky Diodes ◽

Depth Profiling ◽

Thermionic Emission ◽

Barrier Heights ◽

Transient Spectroscopy ◽

State Resistance ◽

Thick Layers

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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Pt Schottky contacts on Ga- and N-face surfaces of free-standing GaN

MRS Proceedings ◽

10.1557/proc-680-e6.8 ◽

2001 ◽

Vol 680 ◽

Author(s):

U. Karrer ◽

C.R. Miskys ◽

O. Ambacher ◽

M. Stutzmann

Keyword(s):

Schottky Diodes ◽

Reverse Current ◽

Forward Direction ◽

Hydride Vapor Phase Epitaxy ◽

Free Standing ◽

Band Bending ◽

Barrier Heights ◽

Consistent Solution ◽

Lift Off ◽

Gap States

ABSTRACTThick GaN films, grown by hydride vapor phase epitaxy (HVPE), were separated from their sapphire substrate with a laser-induced lift-off process. After cleaning and polishing, these films offer the most direct way to investigate and compare the influence of crystal polarity on the electronic properties of Ga-face and N-face surfaces, respectively. Different barrier heights for Pt Schottky diodes evaporated onto Ga- and N-face GaN are determined from the dependence of the effective barrier height versus ideality factor by I-V measurements to 1.15 eV and 0.80 eV, respectively. The charge neutrality condition at the surface is modified by the spontaneous polarization due to the polarization induced bound sheet charge. This effect has to be included in the electronegativity concept of metal induced gap states (MIGS) and can also be illustrated by different band bending of the conduction and valence band, inferred from the self-consistent solution of the Schrödinger-Poisson equation. Furthermore, temperature dependent I-V characteristics are compared to simulated behavior of Schottky diodes, exhibiting excellent agreement in forward direction, but showing deviations in the reverse current.

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4.5 kV-8 A SiC-Schottky Diodes / Si-IGBT Modules

Materials Science Forum ◽

10.4028/www.scientific.net/msf.527-529.1163 ◽

2006 ◽

Vol 527-529 ◽

pp. 1163-1166 ◽

Cited By ~ 1

Author(s):

Dominique Tournier ◽

Peter Waind ◽

Phillippe Godignon ◽

L. Coulbeck ◽

José Millan ◽

...

Keyword(s):

High Voltage ◽

Bulk Material ◽

Schottky Diodes ◽

Power Devices ◽

Large Area ◽

Aerospace Applications ◽

Dc Characteristics ◽

Igbt Modules ◽

Device Processing ◽

Manufacturing Yield

Due to the significant achievements in SiC bulk material growth and in SiC device processing technology, this semiconductor has received a great interest for power devices, particularly for SiC high-voltage Schottky barrier rectifiers. The main difference to ultra fast Si pin diodes lies in the absence of reverse recovery charge in SiC SBDs. This paper reports on 4.5kV-8A SiC Schottky diodes / Si-IGBT modules. The Schottky termination design and the fabrication process gives a manufacturing yield of 40% for large area devices on standard starting material. Modules have been successfully assembled, containing Si-IGBTs and 4.5kV-SiC Schottky diodes and characterized in both static and dynamic regimes. The forward dc characteristics of the modules show an on-resistance of 33mohm.cm2 @ room temperatue (RT) and a very low reverse leakage current density (JR < 10 5A/cm2 @ 3.5kV). An experimental breakdown voltage higher than 4.7kV has been measured in the air on polyimide passivated devices. This value corresponds to a junction termination efficiency of at least 80% according to the epitaxial properties. These SiC SBDs are well suited for high voltage, medium current, high frequency switching aerospace applications, matching perfectly as freewheeling diodes with Si IGBTs.

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Quasi-Schottky Diodes on (n)In.53Ga.47as with Barrier Heights of 0.6 eV

MRS Proceedings ◽

10.1557/proc-240-449 ◽

1991 ◽

Vol 240 ◽

Author(s):

M. Marso ◽

P. Kordoš ◽

R. Meyer ◽

H. Lüth

Keyword(s):

Schottky Barrier ◽

Barrier Height ◽

Schottky Diodes ◽

Reverse Current ◽

Surface Layers ◽

Fully Depleted ◽

Barrier Heights ◽

Effective Barrier ◽

Basic Parameters ◽

And Control

ABSTRACTThe modification and control of the Schottky barrier height on (n)InGaAs is an important tool at the device preparation as the barrier height is very low, øB° = 0.2 eV. We report about the Schottky barrier enhancement on (n)InGaAs by thin fully depleted surface layers of high doped (p+)InGaAs. Structures with different thicknesses of (p+)InGaAs in the range from 8 to 80 nm were grown by LP MOVPE technique and quasi-Schottky diodes with different contact areas were prepared using titanium as a barrier metal. I-V and I-T characteristics were measured and analysed to obtain basic parameters of prepared diodes, i. e. ideality factor n, effective barrier height øB, series resistance Rgand reverse current density JR (1V). The barrier height enhancement increases with the thickness of the (p+)-layer. Effective barrier heights of øB>0.6 eV, i.e. higher than reported until now, can be obtained with the surface layers of (p+)InGaAs with thicknesses exceeding 25 nm.

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High Voltage Diffusion-Welded Stacks on the Basis of SiC Schottky Diodes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.858.790 ◽

2016 ◽

Vol 858 ◽

pp. 790-794 ◽

Cited By ~ 3

Author(s):

Oleg Korolkov ◽

Natalja Sleptsuk ◽

Paul Annus ◽

Raul Land ◽

Toomas Rang

Keyword(s):

Vertical Integration ◽

High Voltage ◽

Recovery Time ◽

Analytical Approach ◽

Schottky Diodes ◽

Reverse Current ◽

Estimation Of Parameters ◽

Reverse Voltage ◽

Zero Bias ◽

Reverse Recovery Time

In the present work we have considered the prototype of the high-voltage diode stack made on the basis of commercial SiC Schottky diodes. Implementation of vertical integration for four diode chips yielded stack with the reverse current of 25 μA under reverse voltage of 6 kV. The capacitance of the stack at zero bias is reduced more than three times in comparison with initial diodes. Reverse recovery time of the stack was 8.0 ns. This paper proposes a convenient analytical approach to the estimation of parameters of modular compositions with vertical architecture.

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Schottky diodes based on 4H-SiC epitaxial layers

Journal of Physics Conference Series ◽

10.1088/1742-6596/2103/1/012235 ◽

2021 ◽

Vol 2103 (1) ◽

pp. 012235

Author(s):

A M Strel’chuk ◽

E V Kalinina

Keyword(s):

Schottky Barrier ◽

Barrier Height ◽

Schottky Barrier Height ◽

Alternative Explanation ◽

Schottky Diodes ◽

Reverse Current ◽

Epitaxial Layers ◽

Barrier Heights ◽

Current Voltage ◽

Significant Spread

Abstract Forward and reverse current-voltage (IV) characteristics of Cr-SiC (4H) Schottky diodes based on epitaxial layers with doping (1-3)· 1015 cm-3 were studied in the temperature range of 300-550 K. It is shown that in many cases the IV characteristics are close to ideal, but a significant spread of the forward IV characteristics of diodes manufactured in the same way on the same epitaxial layer was found, probably due to the spread of the Schottky barrier heights reaching 0.3 eV. Heating of the diode, as well as packaging, can also change the Schottky barrier height. An alternative explanation suggests the presence of a powerful shunt.

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