Reduction in Background Carrier Concentration for 4H-SiC C-face Epitaxial Growth

MRS Advances ◽  
2016 ◽  
Vol 1 (54) ◽  
pp. 3631-3636 ◽  
Author(s):  
Johji Nishio ◽  
Hirokuni Asamizu ◽  
Mitsuhiro Kushibe ◽  
Hidenori Kitai ◽  
Kazutoshi Kojima
Keyword(s):  
Epitaxial Growth ◽  
Carrier Concentration ◽  
Surface Defect ◽  
Carrier Lifetime ◽  
Epitaxial Film ◽  
Defect Density ◽  
Growth Parameters ◽  
Thickness Variation ◽  
Power Devices ◽  
Surface Defect Density

ABSTRACT Reduction in background carrier concentration has been investigated for 4H-SiC C-face epitaxial growth in order to be applied for ultra-high voltage power devices. Optimizing epitaxial growth parameters made it possible to achieve 7.6x1013 cm-3 as the background carrier concentration within a whole area of specular 3-inch wafers. In addition to the background carrier concentration reduction, epitaxial film thickness variation, surface defect density and the carrier lifetime have been confirmed to fulfill the requirements for the devices.

Controlling the Cytotoxicity of CdSe Magic-Sized Quantum Dots as a Function of Surface Defect Density

Nano Letters ◽  
2014 ◽  
Vol 14 (9) ◽  
pp. 5452-5457 ◽  
Author(s):  
Anielle Christine Almeida Silva ◽  
Marcelo José Barbosa Silva ◽  
Felipe Andrés Cordero da Luz ◽  
Danielle Pereira Silva ◽  
Samantha Luara Vieira de Deus ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Surface Defect ◽  
Defect Density ◽  
Surface Defect Density

Influence of aspect ratio and surface defect density on hydrothermally grown ZnO nanorods towards amperometric glucose biosensing applications

2017 ◽  
Vol 422 ◽  
pp. 798-808 ◽  
Author(s):  
Mayoorika Shukla ◽  
Pramila ◽  
Tejendra Dixit ◽  
Rajiv Prakash ◽  
I.A. Palani ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Surface Defect ◽  
Defect Density ◽  
Zno Nanorods ◽  
Glucose Biosensing ◽  
Surface Defect Density

Deposition, Defect and Weak Bond Formation Processes in a-Si:H

1998 ◽  
Vol 507 ◽  
Author(s):  
J Robertson ◽  
M J Powell
Keyword(s):  
Hydrogen Evolution Reaction ◽  
Surface Defect ◽  
Defect Formation ◽  
Defect Density ◽  
Bond Formation ◽  
Surface Processes ◽  
Formation Processes ◽  
Weak Bond ◽  
Further Development ◽  
Surface Defect Density

ABSTRACTThe growth of a-Si:H and the resulting weak bond and defect formation mechanism is analysed in terms of the adsorbed Sill3 model of growth. It is found that this model describes the surface processes well, but it needs further development to correctly describe the temperature dependence of the formation of defects and weak bonds, since the surface defect density decreases monotonically with temperature and does not show a minimum near 250C. We show that the experimentally observed increase in hydrogen content, weak bond and defect density at lower deposition temperatures can be accounted for by a hydrogen evolution reaction from H2* sites.

LaTiO2N nanopowders (NPs) with low surface defect density via nitridation of flame made NPs retaining simple perovskite structure

2022 ◽  
Author(s):  
Yoshiyuki Abe ◽  
Richard M. Laine
Keyword(s):  
Optical Absorption ◽  
Absorption Edge ◽  
Perovskite Structure ◽  
Surface Defect ◽  
Defect Density ◽  
Optical Absorption Edge ◽  
Surface Defect Density

LaTiO2N NP synthesized from flame made LaTiO3 NP exhibits less absorption background above the optical absorption edge than that synthesized from flame made La2Ti2O7 NP, suggesting a low surface defect density.

Development of Epitaxial SiC Processes Suitable for Bipolar Power Devices

2005 ◽  
Vol 483-485 ◽  
pp. 155-158 ◽  
Author(s):  
Joseph J. Sumakeris ◽  
Mrinal K. Das ◽  
Seo Young Ha ◽  
Edward Hurt ◽  
Kenneth G. Irvine ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Growth Process ◽  
Defect Density ◽  
Power Devices ◽  
Extended Defect ◽  
Bipolar Devices ◽  
Significant Barrier ◽  
The Stability ◽  
Vf Drift ◽  
Growth Technology

We present a survey of the most important factors relating to an epitaxial SiC growth process that is suitable for bipolar power devices. During the last several years, we have advanced our hot-wall SiC epitaxial growth technology to the point that we can support the transition of bipolar power devices from demonstrations to applications. Two major concerns in developing a suitable epitaxial technology are epilayer uniformity and extended defect density. Our state-of-theart capability permits the realization of 1-cm2 area devices with exceptional yields. Another major concern is the stability of bipolar devices during forward conduction. We have developed proprietary substrate and epilayer preparation technologies that have essentially eliminated Vf drift as a significant barrier to the exploitation of SiC based bipolar devices.

Improvement of Quality of Thick 4H-SiC Epilayers

2017 ◽  
Vol 897 ◽  
pp. 59-62 ◽  
Author(s):  
Akira Miyasaka ◽  
Kazutoshi Kojima ◽  
Kenji Momose ◽  
Hiroshi Osawa ◽  
Hajime Okumura
Keyword(s):  
Growth Rate ◽  
Epitaxial Growth ◽  
Carrier Concentration ◽  
Stacking Faults ◽  
Power Devices ◽  
Concentration Depth Profile ◽  
Interfacial Dislocations ◽  
By Products ◽  
Dopant Element

The epitaxial growth of ~250 μm thick 4H-SiC epilayers has been demanded for ultra-high-voltage power devices. We have attempted to improve the quality of thick epilayers. At the edge of wafer, stacking faults, epi-crown and interfacial dislocations could be well suppressed by controlling the distribution of growth rate. Investigation of carrier concentration depth profile revealed that increasing surface roughness increased the carrier concentration during thick epitaxial growth. Under N2-doped growth condition, memory effect by accumulation of by-products containing dopant element is also one of the reasons of the carrier concentration increasing during the growth.

High Quality Epitaxial Growth on 4° Off-Axis 4H SiC with Addition of HCl

2008 ◽  
Vol 600-603 ◽  
pp. 103-106 ◽  
Author(s):  
Jie Zhang ◽  
Janice Mazzola ◽  
Swapna G. Sunkari ◽  
Gray Stewart ◽  
Paul B. Klein ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Room Temperature ◽  
Carrier Lifetime ◽  
Defect Density ◽  
Free Exciton ◽  
High Quality ◽  
Pin Diodes ◽  
Time Resolved ◽  
Good Surface ◽  
Comprehensive Characterization

Epitaxial growth of 3-in, 4° off-axis 4H SiC with addition of HCl has been presented. Good surface morphology with a low defect density has been obtained, even for epi thickness of 38 µm. Comprehensive characterization techniques conducted on the epi material obtained in this process have independently confirmed the high purity and low density of crystalline imperfections. Low temperature PL displays clear free exciton I77 recombination while no L1 line is discernable. DLTS measurements have confirmed a low concentration of Z1/2 and EH6/7 below or in the range of 1011 cm-3. Time resolved PL at room temperature performed on a 38 µm thick epi wafer gives long carrier lifetime in the range of 1.5 to above 5 µsec. PiN diodes with diode area up to 25 mm2 have demonstrated blocking voltages above 900V, with a max electric field of above 2.5 MV/cm.

Homo-Epitaxial Growth on 2° Off-Cut 4H-SiC(0001) Si-Face Substrates Using H2-SiH4-C3H8 CVD System

2014 ◽  
Vol 778-780 ◽  
pp. 214-217 ◽  
Author(s):  
Kentaro Tamura ◽  
Chiaki Kudou ◽  
Keiko Masumoto ◽  
Johji Nishio ◽  
Kazutoshi Kojima
Keyword(s):  
Confocal Microscopy ◽  
Epitaxial Growth ◽  
Carrier Concentration ◽  
Epitaxial Layer ◽  
Defect Density ◽  
Epitaxial Layers ◽  
Differential Interference Contrast ◽  
Step Bunching

We have grown epitaxial layers on 2° off-cut 4H-SiC(0001) Si-face substrates. The epitaxial layer surfaces on 2° off-cut substrates are more prone to generate step-bunching than on 4° off-cut substrates, which are observed by confocal microscopy with differential interference contrast. We have speculated that the step-bunching is generated at the beginning of an epitaxial growth. Triangular defect density of epitaxial layers on 2° off-cut substrates is as low as 0.7 cm–2 for the size corresponding to 150 mm. We have firstly reported distribution of 2° off-cut epitaxial layers for the 150-mm size using two 76.2-mm wafers: σ/mean = 3.3% for thickness, σ/mean = 7.3% for carrier concentration.

Epitaxial Growth of SiC in a Vertical Multi-Wafer CVD System: Already Suited as Production Process?

1999 ◽  
Vol 572 ◽  
Author(s):  
Roland Rupp ◽  
Christian Hecht ◽  
Arno Wiedenhofer ◽  
Dietrich Stephani
Keyword(s):  
Epitaxial Growth ◽  
Gas Flow ◽  
Defect Density ◽  
Schottky Diodes ◽  
Impurity Level ◽  
Thickness Variation ◽  
Epitaxial Layers ◽  
Growth Step ◽  
Low Leakage ◽  
Low Leakage Current

ABSTRACTResults about a new CVD system suited for epitaxial growth on six 2 inch SiC-wafers at a time are presented. Excellent gas flow stability is achieved for this new reactor type as shown by in- situ observations of the gas flow dynamics in the reactor chamber. These experimental results agree favorably with numerical process simulation results.The epitaxial layers grown in the multi-wafer system so far show a by an order of magnitude higher background impurity level (≤1015 cm−3) as reported previously for layers grown in single-wafer systems by the authors and other groups (≤ 1014 cm−3). On the other hand, the doping homogeneity achieved until today is very encouraging. The variation on a 2 inch wafer is less than ± 20% at about 1*1016 cm−3. The wafer to wafer variation of the average doping value both within a run and from run to run is within 15 %. The reproducibility and uniformity of the layer thickness is even better (total thickness variation ≤5% on a 2 inch wafer). The surface of the epitaxial layers is very smooth with a typical growth step height of 0.5 nm (4H, 8° off orientation). First measurements on Schottky diodes build on these layers show low leakage current values indicating low point defect density in the epitaxial layers.

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