A Study of Deep Energy-Level Traps at the 4H-SiC/SiO2 Interface and Their Passivation by Hydrogen

This study is focused on characterization of deep energy-level interface traps formed during sodium enhanced oxidation of n-type Si face 4H-SiC. The traps are located 0.9 eV below the SiC conduction band edge as revealed by deep level transient spectroscopy. Furthermore these traps are passivated using post-metallization anneal at 400°C in forming gas ambient.

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Deep-Level Transient Spectroscopy Characterization of Interface States in SiO2/4H-SiC Structures Close to the Conduction Band Edge

Materials Science Forum ◽

10.4028/www.scientific.net/msf.778-780.424 ◽

2014 ◽

Vol 778-780 ◽

pp. 424-427

Author(s):

Tetsuo Hatakeyama ◽

Mitsuru Sometani ◽

Kenji Fukuda ◽

Hajime Okumura ◽

Tsunenobu Kimoto

Keyword(s):

Electron Density ◽

Conduction Band ◽

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Interface States ◽

Band Edge ◽

Conduction Band Edge ◽

Capture Process ◽

Oxide Trap ◽

Transient Spectroscopy

Constant-capacitance deep-level transient spectroscopy was carried out to characterize in detail interface states close to the conduction band edge in SiO2/SiC structures. The measured results are summarized as follows: (1) The capture of electrons by the interface states proceeds logarithmically with time. (2) The emission of electrons accelerates slightly with increasing density of captured electrons. The oxide trap model explains the logarithmic change in capture with time but not the phenomenon of accelerated emissions. This prompted us to formulate a new model that replicates the logarithmic capture process with time. In this model, we postulated the electron density at the interface decreases exponentially as the trapped electron density increases owing to the interaction between the trapped electrons and the free electrons. In this case, the capture process is almost the same as with the oxide trap model except for the definition of parameters. Further, we do not need to take into account the delay of the emission process caused by tunneling. The phenomenon of accelerated emissions may be explained by interactions among captured electrons in this model.

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Electrical Characterization of 1 keV He-, Ne-, and Ar-Ion Bombarded n-Si Using Deep Level Transient Spectroscopy

MRS Proceedings ◽

10.1557/proc-510-519 ◽

1998 ◽

Vol 510 ◽

Author(s):

P.N.K. Deenapanray ◽

F.D. Auret ◽

M.C. Ridgway ◽

S.A. Goodman ◽

G. Myburg

Keyword(s):

Conduction Band ◽

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Electrical Characterization ◽

Ion Bombardment ◽

Thermally Stable ◽

Vacancy Clusters ◽

Transient Spectroscopy ◽

Low Energy Ions

AbstractWe report on the electrical properties of defects introduced in epitaxially grown n-Si by 1 keV He-, Ne-, and Ar-ion bombardment. Epitaxial layers with different O contents were used in this study. We demonstrate using deep level transient spectroscopy that the low energy ions introduced a family of similarly structured defects (DI) with electronic levels at ∼0.20 eV below the conduction band. The introduction of this set of identical defects was not influenced by the presence of O. Ion bombardment of O-rich Si introduced another family of prominent traps (D2) with levels close to the middle of the band gap. Both sets of defects were thermally stable up to ∼400 °C, and their annealing was accompanied by the introduction of a family of secondary defects (D3). The “D3” defects had levels at ∼0.21 eV below the conduction band and were thermally stable at 650 °C. We have proposed that the “DI”, “D2”, and “D3” defects are higherorder vacancy clusters (larger than the divacancy) or complexes thereof.

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Characterization of traps in SiC/SiO2interfaces close to the conduction band by deep-level transient spectroscopy

Japanese Journal of Applied Physics ◽

10.7567/jjap.54.111301 ◽

2015 ◽

Vol 54 (11) ◽

pp. 111301 ◽

Cited By ~ 10

Author(s):

Tetsuo Hatakeyama ◽

Mitsuru Sometani ◽

Kenji Fukuda ◽

Hajime Okumura ◽

Tsunenobu Kimoto

Keyword(s):

Conduction Band ◽

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Transient Spectroscopy

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Cryogenic Characterization of NH3 Post Oxidation Annealed 4H-SiC Trench MOSFETs

Materials Science Forum ◽

10.4028/www.scientific.net/msf.963.175 ◽

2019 ◽

Vol 963 ◽

pp. 175-179

Author(s):

Judith Berens ◽

Gregor Pobegen ◽

Thomas Aichinger ◽

Gerald Rescher ◽

Tibor Grasser

Keyword(s):

Nitric Oxide ◽

Conduction Band ◽

Thermal Emission ◽

Current Method ◽

Band Edge ◽

Conduction Band Edge ◽

Interface Traps ◽

Two Peaks ◽

Trap Levels

We employed the thermal dielectric relaxation current method (TDRC) for the cryogenic characterization of ammonia (NH3) post oxidation annealed 4H silicon carbide (4H-SiC) trench MOSFETs. We studied differences and similarities between annealing in nitric oxide (NO) and NH3. In NO and NH3 annealed trench MOSFETs, the same type of traps was found near the conduction band edge of 4H-SiC. The TDRC-signal consists of two peaks caused by interface states with a thermal emission barrier of 0.13 eV and near interface traps (NITs) with an emission barrier of approximately 0.3 eV. Significantly more interface traps close to the conduction band edge were found for the NH3 annealed devices compared to the NO annealed ones. Our TDRC results indicate that NH3 post oxidation anneal (POA) affects trap levels in a different way than NO POA.

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Deep Traps in 4H-SiC MOS Capacitors Investigated by Deep Level Transient Spectroscopy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.778-780.603 ◽

2014 ◽

Vol 778-780 ◽

pp. 603-606 ◽

Cited By ~ 2

Author(s):

Einar Ö. Sveinbjörnsson ◽

Olafur Gíslason

Keyword(s):

Thermal Oxidation ◽

Conduction Band ◽

High Temperatures ◽

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Conduction Band Edge ◽

Mos Capacitors ◽

Deep Traps ◽

Transient Spectroscopy ◽

Very High

Using Deep Level Transient Spectroscopy (DLTS) on n-type MOS capacitors we find that thermal oxidation of 4H-SiC produces deep traps at or near the SiO2/SiC interface with two well defined DLTS peaks. The traps are located ~ 0.85 V and ~ 1.0 eV below the SiC conduction band edge and are present in wet and dry oxides as well as oxides produced by sodium enhanced oxidation and oxides grown in N2O. The deep traps are located at the SiO/SiC interface after oxidation at 1150°C but do extend further into the SiC epilayer after oxidation at 1240°C. We identify these traps as ON1 and ON2 which been observed in epitaxial layers after oxidation at very high temperatures (1200-1500°C) [.

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Deep Level Characterization of 5 MeV Proton Irradiated SiC PiN Diodes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.858.308 ◽

2016 ◽

Vol 858 ◽

pp. 308-311 ◽

Cited By ~ 2

Author(s):

Giovanni Alfieri ◽

Andrei Mihaila ◽

Hussein M. Ayedh ◽

Bengt Gunnar Svensson ◽

Pavel Hazdra ◽

...

Keyword(s):

Energy Range ◽

Minority Carrier ◽

Deep Level ◽

Band Edge ◽

Conduction Band Edge ◽

Minority Charge Carrier ◽

Carrier Traps ◽

Transient Spectroscopy ◽

The Impact

In this contribution, we report on the electrical characterization of point defects in 4H-SiC p+in diodes. Ten electrically active levels have been detected in the base region of the devices, by employing Deep Level Transient Spectroscopy (DLTS) and Minority Carrier Transient Spectroscopy (MCTS). Of these ten levels, six are majority carrier traps, in the 0.1-1.7 eV energy range below the conduction band edge, and four were minority carrier traps located in the 0.13-0.4 eV energy range above the valence band edge. We found that, during DLTS measurements, both majority and minority carrier traps can be detected and we explain this by considering the behavior of the quasi-Fermi levels. At last, we studied the impact of proton irradiation on the minority charge carrier lifetime.

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Hydrogen Decoration of Vacancy Related Complexes in Hydrogen Implanted Silicon

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.178-179.192 ◽

2011 ◽

Vol 178-179 ◽

pp. 192-197 ◽

Cited By ~ 5

Author(s):

Helge Malmbekk ◽

Lasse Vines ◽

Edouard V. Monakhov ◽

Bengt Gunnar Svensson

Keyword(s):

Conduction Band ◽

Deep Level Transient Spectroscopy ◽

Minority Carrier ◽

Deep Level ◽

Conduction Band Edge ◽

Absolute Concentrations ◽

Transient Spectroscopy ◽

P Type ◽

Induced Defects ◽

Irradiation Induced Defects

Interaction between hydrogen (H) and irradiation induced defects in p-type silicon (Si) have been studied in H implanted pn-junctions, using deep level transient spectroscopy (DLTS), as well as minority carrier transient spectroscopy (MCTS). Two H related levels at Ev+0.27 eV and Ec-0.32 eV have been observed (Ev and Ec denote the valence and conduction band edge, respectively). Both levels form after a 10 min anneal at 125C, concurrent with the release of H from the boron-hydrogen (B-H) complex. The correlated formation rates and absolute concentrations of the two levels support the notion that they are due to the same defect. In addition, a level at Ec-0.45 eV is observed and discussed in terms of vacancy-hydrogen related defects.

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Deep-Level-Transient Spectroscopy Characterization of Mobility-Limiting Traps in SiO2/SiC Interfaces on C-Face 4H-SiC

Materials Science Forum ◽

10.4028/www.scientific.net/msf.740-742.477 ◽

2013 ◽

Vol 740-742 ◽

pp. 477-480 ◽

Cited By ~ 7

Author(s):

Tetsuo Hatakeyama ◽

T. Shimizu ◽

T. Suzuki ◽

Y. Nakabayashi ◽

Hajime Okumura ◽

...

Keyword(s):

Conduction Band ◽

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Interface State ◽

State Density ◽

Interface State Density ◽

Channel Mobility ◽

Transient Spectroscopy ◽

Density Of Interface States

Constant-capacitance deep-level-transient spectroscopy (CCDLTS) characterization of traps (or states) in SiO2/SiC interfaces on the C-face was carried out to clarify the cause of low-channel mobility of SiC MOSFETs. CCDLTS measurements showed that the interface-state density (Dit) near the conduction band of SiO2/SiC interfaces fabricated using N2O oxidation was much higher than that of SiO2/SiC interfaces fabricated using wet oxidation. The high density of interface states near the conduction band is likely to be the main cause of the low mobility of MOSFETs fabricated using N2O oxidation.

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Electrical Characterization of Proton Irradiated n-Type ZnO

MRS Proceedings ◽

10.1557/proc-0957-k03-08 ◽

2006 ◽

Vol 957 ◽

Author(s):

F Danie Auret ◽

Michael Hayes ◽

Jackie Nel ◽

Walter Meyer ◽

Pieter Johan Janse van Rensburg ◽

...

Keyword(s):

Conduction Band ◽

Deep Level Transient Spectroscopy ◽

Proton Irradiation ◽

Deep Level ◽

Electrical Characterization ◽

Low Concentrations ◽

Transient Spectroscopy ◽

Induced Defects ◽

Irradiation Induced Defects

ABSTRACTRu Schottky barrier diodes (SBD's) were fabricated on the Zn face of n-type ZnO. These diodes were irradiated with 1.8 MeV at fluences ranging from 1 ´ 1013 cm-2 to 2.4 ´ 1014 cm-2. Capacitance and current (I) deep level transient spectroscopy (DLTS) was used to characterise the irradiation induced defects. Capacitance DLTS showed that proton irradiation introduced a level, Ep1, at 0.52 eV below the conduction band at an introduction rate of 13±1 cm-1. A defect with a very similar DLTS signature was also present in low concentrations in unirradiated ZnO. I-DLTS revealed that this proton irradiation introduced a defect with an energy level at (0.036± 0.004) eV below the conduction band. This defect is clearly distinguishable from a defect with a level at (0.033± 0.004) eV below the conduction band that was present in the unirradiated sample. It is speculated that these shallow level defects are related to zinc interstitials or complexes involving them.

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