Properties of Thermally Etched 4H-SiC by Chlorine-Oxygen System

2007 ◽  
Vol 556-557 ◽  
pp. 283-286
Author(s):  
Tomoaki Hatayama ◽  
S. Takenami ◽  
Hiroshi Yano ◽  
Yukiharu Uraoka ◽  
Takashi Fuyuki
Keyword(s):  
Crystal Defects ◽  
Induced Current ◽  
Etch Pits ◽  
Thermal Etching ◽  
Oxygen System ◽  
Basal Plane Dislocation ◽  
Electron Beam Induced Current ◽  
Planar Mapping ◽  
Etched Surface ◽  
The Relationship

By the use of Cl2-O2 thermal etching method, the etching rates of 4H-SiC were reached to about 1μm/h for Si and 40μm/h for C face at 950oC. Etch pits only appeared over 0.25-μm-etched depth on the 4H-SiC (0001) Si face. The shapes and density of etch pits are similar tendencies in the case of molten KOH etched surface. To study the relationship between thermally etched surface features and crystal defects, the planar mapping electron-beam-induced current (EBIC) technique was carried out. Almost dark areas in the EBIC image correspond to the etch pits. From the EBIC image, a shell-like pit formed by the Cl2-O2 etching on the (0001) Si face is a basal plane dislocation.

3-Dimensional Non-Destructive Dislocation Analyses in SiC Measured by Planar Electron-Beam-Induced Current Method

2006 ◽  
Vol 527-529 ◽  
pp. 423-426 ◽  
Author(s):  
Y. Yanagisawa ◽  
Tomoaki Hatayama ◽  
Hiroshi Yano ◽  
Yukiharu Uraoka ◽  
Takashi Fuyuki
Keyword(s):  
Schottky Contact ◽  
Current Method ◽  
Induced Current ◽  
3 Dimensional ◽  
Depth Position ◽  
Basal Plane Dislocation ◽  
Electron Beam Induced Current ◽  
Planar Mapping ◽  
Planar Electron ◽  
Non Destructive

Propagations of dislocations in 4H-SiC were evaluated three-dimensionally by a planar mapping EBIC method with the control of accelerating voltages. Screw dislocation (SD), edge dislocation (ED), and basal plane dislocation (BPD) were clearly observed through the 20nm-thick Ni Schottky contact on SiC. From the analysis of BPD extended on {0001}, the intensity of EBIC signals was proportional to the depth position of defect. In addition, the information of the decomposition and combination for dislocations can be obtained from the fluctuation of EBIC signal along the scanning position.

Performance of Silicon Carbide PiN Diodes Fabricated on Basal Plane Dislocation-Free Epilayers

2006 ◽  
Vol 527-529 ◽  
pp. 371-374 ◽  
Author(s):  
Ze Hong Zhang ◽  
A.E. Grekov ◽  
Priyamvada Sadagopan ◽  
S.I. Maximenko ◽  
Tangali S. Sudarshan
Keyword(s):  
Basal Plane ◽  
Stacking Faults ◽  
Surface Damage ◽  
Induced Current ◽  
Pin Diodes ◽  
Current Stressing ◽  
Forward Current ◽  
Nucleation Sites ◽  
Basal Plane Dislocation ◽  
Electron Beam Induced Current

The nucleation sites of stacking faults (SFs) during forward current stress operation of 4H-SiC PiN diodes were investigated by the electron beam induced current (EBIC) mode of scanning electron microscopy (SEM), and the primary SF nucleation sites were found to be basal plane dislocations (BPDs). Damage created on the diode surface also acts as SF nucleation sites. By using a novel BPD-free SiC epilayer, and avoiding surface damage, PiN diodes were fabricated which did not exhibit SF formation under current stressing at 200A/cm2 for 3 hours.

EBIC Analysis of Breakdown Failure Point in 4H-SiC PiN Diodes

2009 ◽  
Vol 615-617 ◽  
pp. 707-710 ◽  
Author(s):  
Takasumi Ohyanagi ◽  
Chen Bin ◽  
Takashi Sekiguchi ◽  
Hirotaka Yamaguchi ◽  
Hirofumi Matsuhata
Keyword(s):  
Metal Contamination ◽  
Avalanche Breakdown ◽  
Induced Current ◽  
Pin Diodes ◽  
X Ray ◽  
Basal Plane Dislocation ◽  
Failure Point ◽  
Electron Beam Induced Current ◽  
Emission Microscopy ◽  
Permittivity Change

The breakdown failure points in the 4H-SiC PiN diodes were analyzed by the electron beam induced current (EBIC). We focused on the failure, which showed the avalanche breakdown, and we determined the failure points by an emission microscopy. We observed the basal plane dislocation around the failure point and at measured temperatures below 200K we found the dark spots in the EBIC. However, in the X-ray topography image, no spots were found around the dislocations. We therefore think that these spots originated from the metal contamination. The electric field was multiplied due to a permittivity change, and this multiplication caused the avalanche breakdown.

Effect of Crystal Defects on Reverse I-V Characteristics of 4H-SiC APDs

2006 ◽  
Vol 527-529 ◽  
pp. 427-430
Author(s):  
Stanislav I. Soloviev ◽  
Peter M. Sandvik ◽  
Steve Arthur ◽  
Kevin Matocha ◽  
S.I. Maximenko ◽  
...  
Keyword(s):  
Short Pulse ◽  
Avalanche Photodiodes ◽  
Crystal Defects ◽  
Structural Defects ◽  
Type I ◽  
Type Ii ◽  
Thermal Breakdown ◽  
Induced Current ◽  
Electron Beam Induced Current ◽  
Free Area

In this work, we investigated the effect of crystal defects on reverse I-V characteristics of avalanche photodiodes (APDs) using electron-beam induced current (EBIC) mode of SEM. Two types of SiC APD structures (I and II) were fabricated using 2 inch p-doped substrates with n-doped epilayers and 3 inch n-doped substrates with p- and n- epilayers. Areas of the formed diodes were approximately 1 mm2. The devices without any kind of electrically active 3-D structural defects demonstrated breakdown voltages close to theoretical values, ~500 V for the APD Type I and ~1200 V for Type II APD. Stability of Type I devices was tested by applying a short pulse of high voltage (~800 V). EBIC images, taken prior to and after the failure test, showed new defects in the dislocation free area, which, presumably, were caused by thermal breakdown.

Nondestructive Analysis of Crystal Defects in 4H-SiC Epilayer by Devised Electron-Beam-Induced Current Method

2005 ◽  
Vol 44 (No. 41) ◽  
pp. L1271-L1274 ◽  
Author(s):  
Satoshi Nitani ◽  
Tomoaki Hatayama ◽  
Kenji Yamaguchi ◽  
Hiroshi Yano ◽  
Yukiharu Uraoka ◽  
...  
Keyword(s):  
Electron Beam ◽  
Current Method ◽  
Crystal Defects ◽  
Induced Current ◽  
Nondestructive Analysis ◽  
Electron Beam Induced Current

Photoluminescence and EBIC for Process Control and Failure Analysis in Si-Based Photovoltaics

2010 ◽  
Author(s):  
Martin Kittler ◽  
Tzanimir Arguirov ◽  
Reiner Schmid ◽  
Winfried Seifert ◽  
Teimuraz Mchedlidze
Keyword(s):  
Solar Cells ◽  
Process Control ◽  
Crystalline Silicon ◽  
Crystal Defects ◽  
Induced Current ◽  
Line Defect ◽  
Electron Beam Induced Current ◽  
Solar Si ◽  
Nondestructive Characterization

Abstract Crystalline silicon used for fabrication of solar cells, such as multicrystalline silicon (mc-Si), contains a high density of extended crystal defects. Since mc-Si wafers exhibit an inhomogeneous defect distribution, there is a need to combine the spectral capabilities with the ability of spatially resolving the defect areas. This paper reports application of luminescence and electron-beam-induced current (EBIC) techniques for characterization of defects in solar Si. The first part introduces luminescence features of defective Si and discusses application examples. The second part starts with explanation of the EBIC technique, including details about the temperature dependence of the EBIC defect contrast c(T). Then, application examples of the c(T) behavior and the analysis of the "interaction" of grain boundaries with p-n junctions are discussed. The paper demonstrates the potential of luminescence for nondestructive characterization of Si wafers and solar cells in terms of in-line defect detection and process control.

Electron beam induced current study of thin silicon layers on insulator substrate

1990 ◽  
Vol 48 (4) ◽  
pp. 618-619
Author(s):  
A. Buczkowski ◽  
Z. J. Radzimski ◽  
J. C. Russ ◽  
G. A. Rozgonyi
Keyword(s):  
Electron Beam ◽  
Energy Loss ◽  
Beam Energy ◽  
Collection Efficiency ◽  
Silicon Layer ◽  
Depletion Layer ◽  
Incident Electron Energy ◽  
Induced Current ◽  
Electron Hole ◽  
Electron Beam Induced Current

If a thickness of a semiconductor is smaller than the penetration depth of the electron beam, e.g. in silicon on insulator (SOI) structures, only a small portion of incident electrons energy , which is lost in a superficial silicon layer separated by the oxide from the substrate, contributes to the electron beam induced current (EBIC). Because the energy loss distribution of primary beam is not uniform and varies with beam energy, it is not straightforward to predict the optimum conditions for using this technique. Moreover, the energy losses in an ohmic or Schottky contact complicate this prediction. None of the existing theories, which are based on an assumption of a point-like region of electron beam generation, can be used satisfactorily on SOI structures. We have used a Monte Carlo technique which provide a simulation of the electron beam interactions with thin multilayer structures. The EBIC current was calculated using a simple one dimensional geometry, i.e. depletion layer separating electron- hole pairs spreads out to infinity in x- and y-direction. A point-type generation function with location being an actual location of an incident electron energy loss event has been assumed. A collection efficiency of electron-hole pairs was assumed to be 100% for carriers generated within the depletion layer, and inversely proportional to the exponential function of depth with the effective diffusion length as a parameter outside this layer. A series of simulations were performed for various thicknesses of superficial silicon layer. The geometries used for simulations were chosen to match the "real" samples used in the experimental part of this work. The theoretical data presented in Fig. 1 show how significandy the gain decreases with a decrease in superficial layer thickness in comparison with bulk material. Moreover, there is an optimum beam energy at which the gain reaches its maximum value for particular silicon thickness.

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