The Influence of In-Grown Stacking Faults on the Reverse Current-Voltage Characteristics of 4H-SiC Schottky Barrier Diodes

2007 ◽  
Vol 556-557 ◽  
pp. 885-888 ◽  
Author(s):  
Shin Harada ◽  
Yasuo Namikawa
Keyword(s):  
Basal Plane ◽  
Great Influence ◽  
Reverse Current ◽  
Isosceles Triangle ◽  
Etch Pits ◽  
Leakage Currents ◽  
Planar Fault ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Koh Etching

The area where 4H-SiC SBDs showed high reverse currents was extracted. After KOH etching, the in-grown SF on the basal plane, composed of a straight etch line with a pair of tilted oval pits and additional etch pits forming an isosceles triangle, was observed on some devices. All of the devices containing this SF structure showed large reverse leakage currents in spite of the good forward I-V characteristics. We speculate that this in-grown SF includes another planar fault on the {1-100} plane besides the basal plane which has a great influence on reverse currents of SBDs.

The Effect of Doping Concentration and Conductivity Type on Preferential Etching of 4H-SiC by Molten KOH

2004 ◽  
Vol 815 ◽  
Author(s):  
Ying Gao ◽  
Zehong Zhang ◽  
Robert Bondokov ◽  
Stanislav Soloviev ◽  
Tangali Sudarshan
Keyword(s):  
Thermal Diffusion ◽  
Basal Plane ◽  
Doping Concentration ◽  
Structural Defects ◽  
Etch Pits ◽  
Conductivity Type ◽  
Isotropic Etching ◽  
Electrochemical Processes ◽  
P Type ◽  
Koh Etching

AbstractMolten KOH etchings were implemented to delineate structural defects in the n- and ptype 4H-SiC samples with different doping concentrations. It was observed that the etch preference is significantly influenced by both the doping concentrations and the conductivity types. The p-type Si-face 4H-SiC substrate has the most preferential etching property, while it is least for n+ samples. It has been clearly demonstrated that the molten KOH etching process involves both chemical and electrochemical processes, during which isotropic etching and preferential etching are competitive. The n+ 4H-SiC substrate was overcompensated via thermal diffusion of boron to p-type and followed by molten KOH etching. Three kinds of etch pits corresponding to threading screw, threading edge, and basal plane dislocations are distinguishably revealed. The same approach was also successfully employed in delineating structural defects in (0001) C-face SiC wafers.

ELECTROMECHANICAL CHARACTERISTICS OF POLYVINYLIDENE FLUORIDE FOR FLEXIBLE ELECTRONICS

2013 ◽  
Vol 37 (3) ◽  
pp. 325-333 ◽  
Author(s):  
Wen-Yang Chang ◽  
Cheng-Hung Hsu
Keyword(s):  
Flexible Electronics ◽  
Polyvinylidene Fluoride ◽  
Input Voltage ◽  
Pvdf Film ◽  
Resistive Load ◽  
X Ray Diffraction ◽  
Leakage Currents ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Stress Cycles

The electromechanical characteristics of PVDF are investigated, including the crystallization, frequency responses, hysteresis, leakage currents, current-voltage characteristics, and fatigue characteristics using X-ray diffraction and an electrometer. Results show that the frequency band of PVDF increases with increasing resistive load and capacitance. The hysteresis area of ΔH slightly increases with increasing input voltage. The magnitude of the current values increases with decreasing delay time at a given drive voltage. PVDF film induced larger degradation when the number of stress cycles was increased to about 105 cumulative cycles.

High-Temperature (up to 800 K) Operation of 6-kV 4H-SiC Junction Diodes

2006 ◽  
Vol 527-529 ◽  
pp. 1339-1342 ◽  
Author(s):  
Michael E. Levinshtein ◽  
Pavel A. Ivanov ◽  
Mykola S. Boltovets ◽  
Valentyn A. Krivutsa ◽  
John W. Palmour ◽  
...  
Keyword(s):  
Deep Level ◽  
Reverse Current ◽  
Differential Resistance ◽  
Base Resistance ◽  
Small Current ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Increasing Temperature ◽  
Surface Leakage ◽  
And Diffusion

Steady-state and transient characteristics of packaged 6-kV 4H-SiC junction diodes have been investigated in the temperature range Т = 300 – 773 К. Analysis of the forward current-voltage characteristics and reverse current recovery waveforms shows that the lifetimeτ of non-equilibrium carriers in the base of the diodes steadily increases with temperature across the entire temperature interval. The rise in τ and decrease in carrier mobilities and diffusion coefficients with increasing temperature nearly compensate each other as regards their effect on the differential resistance of the diode, Rd. As a result, Rd is virtually temperature independent. An appreciable modulation of the base resistance takes place at room temperature even at a relatively small current density j of 20 A/cm2. At T = 800 K and j = 20 A/cm2, a very deep level of the base modulation has been observed. The bulk reverse current is governed by carrier generation in the space-charge region via a trap with activation energy of 1.62 eV. The surface leakage current of packaged structures does not exceed 2×10-6 А at T = 773 K and a reverse bias of 300 V.

Al+ Implanted 4H-SiC p+-i-n Diodes: Evidence for Post-Implantation-Annealing Dependent Defect Activation

2014 ◽  
Vol 778-780 ◽  
pp. 657-660 ◽  
Author(s):  
Ulrike Grossner ◽  
Francesco Moscatelli ◽  
Roberta Nipoti
Keyword(s):  
Activation Energy ◽  
Ideality Factor ◽  
Reverse Current ◽  
Activation Energies ◽  
Forward Current ◽  
Current Voltage ◽  
Different Temperatures ◽  
Current Voltage Characteristics ◽  
The One ◽  
Post Implantation

Two families of Al+implanted vertical p+in diodes that have been processed all by identical steps except the post implantation annealing one have been characterized with current voltage measurements from -100 to +5V at different temperatures. Analysis of the static forward current voltage characteristics shows two different ideality factor regions, which are distinct for each family. The reverse current voltage characteristics reveals corresponding two different activation energies. These are assumed to be correlated to the Z1/2defect for the one case and another one with an activation energy of 0.25eV.

Dislocation Revelation in Highly Doped N-Type 4H-SiC by Molten KOH Etching with Na2O2 Additive

2011 ◽  
Vol 679-680 ◽  
pp. 290-293 ◽  
Author(s):  
Yong Zhao Yao ◽  
Yukari Ishikawa ◽  
Yoshihiro Sugawara ◽  
Hiroaki Saitoh ◽  
Katsunori Danno ◽  
...  
Keyword(s):  
Electron Concentration ◽  
Basal Plane ◽  
Wet Etching ◽  
Etch Pits ◽  
Screw Dislocations ◽  
Edge Dislocations ◽  
Koh Etching

We have proposed a new wet etching recipe using molten KOH and Na2O2 as the etchant (“KN etching”) for dislocation revelation in highly doped n-type 4H-SiC (n+-4H-SiC). Threading screw dislocations (TSDs) and threading edge dislocations (TEDs) have been clearly revealed as hexagonal etch pits differing in pit sizes, and basal plane dislocations (BPDs) as seashell-shaped pits. This new etching recipe has provided a solution to the problem that conventional KOH etching is not effective for dislocation identification in 4H-SiC if the electron concentration is high (>mid-1018 cm-3). We have investigated the effect of SiC off-cut angle on KN etching and it has been shown that the “KN etching” is applicable for the n+-SiC substrate with off-angle from 0o to 8o.

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