Defects Induced by Reactive Ion Etching in Ge Substrate

We investigated impacts of the Ar and CF4　plasma during reactive ion etching (RIE) on defect formation in the Ge substrates using the deep-level-transient-spectroscopy (DLTS) technique. It was found that the Ar plasma causes the roughening of the Ge surface. Moreover, the Ar plasma induces a defect with an energy level of 0.31 eV from the conduction band minimum in the Ge substrate, confirming by DLTS spectra. On the other hand, the CF4plasma hardly induces the surface roughness of Ge. However, the CF4plasma induces many kinds of electron and hole traps. It should be noted that the defects associated with Sb and interstitials are widely distributed to around 3-µm.

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Reactive-Ion-Etching Induced Deep Levels Observed in n-Type and p-Type 4H-SiC

Materials Science Forum ◽

10.4028/www.scientific.net/msf.645-648.759 ◽

2010 ◽

Vol 645-648 ◽

pp. 759-762

Author(s):

Koutarou Kawahara ◽

Giovanni Alfieri ◽

Michael Krieger ◽

Tsunenobu Kimoto

Keyword(s):

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Reactive Ion Etching ◽

Deep Levels ◽

Total Density ◽

Ion Etching ◽

Initial Concentration ◽

Grown Sample ◽

Transient Spectroscopy ◽

P Type

In this study, deep levels are investigated, which are introduced by reactive ion etching (RIE) of n-type/p-type 4H-SiC. The capacitance of as-etched p-type SiC is remarkably small due to compensation or deactivation of acceptors. These acceptors can be recovered to the initial concentration of the as-grown sample after annealing at 1000oC. However, various kinds of defects remain at a total density of ~5× 1014 cm-3 in a surface-near region from 0.3 μm to 1.0 μm even after annealing at 1000oC. The following defects are detected by Deep Level Transient Spectroscopy (DLTS): IN2 (EC – 0.35 eV), EN (EC – 1.6 eV), IP1 (EV + 0.35 eV), IP2 (HS1: EV + 0.39 eV), IP4 (HK0: EV + 0.72 eV), IP5 (EV + 0.75 eV), IP7 (EV + 1.3 eV), and EP (EV + 1.4 eV). These defects generated by RIE can be significantly reduced by thermal oxidation and subsequent annealing at 1400oC.

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Deep Level Transient Spectroscopy of Defects Induced by the Combination of CF4 Reactive Ion Etching and Oxidation in Metal-Oxide-Silicon Capacitors.

MRS Proceedings ◽

10.1557/proc-148-421 ◽

1989 ◽

Vol 148 ◽

Author(s):

Dominique Vuillaume ◽

Jeff P. Gambino

Keyword(s):

Metal Oxide ◽

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Reactive Ion Etching ◽

Interface States ◽

Ion Etching ◽

Mos Capacitors ◽

Metal Oxide Silicon ◽

Transient Spectroscopy ◽

Induced Defects

ABSTRACTMetal-Oxide-silicon (MOS) capacitors have been fabricated on CFb reactive ion etched silicon (n and p types) in order to study the defects at the Si-Si02 interface and in the bulk of the substrate, produced by the combination of reactive ion etching (RIE) and oxidation. Bulk defects and fast interface states are analysed by Deep Level Transient Spectroscopy (DLTS) and the slow interface states in the oxide layer near the interface are probed by Tunnel-DLTS. A density of fast interface states in the range 1010-1011 cm−2 eV−1 is observed for capacitors (both n and p types) fabricated with either dry or wet oxidations, and is probably due to disrupted or strained bonds at the Si-SiO2 interface. The observation of bulk defects in the wet-RIE oxide samples but not in the dry-RIE oxide samples may be related to the shorter oxidation time for wet oxides (31mn) compared to dry oxides(190mn) and explained by a greater annealing of RIE induced defects during the dry oxidation. The bulk traps are identified to be related to carbon contamination, in SiC form, introduced during RIE. Finally, an increase of the slow interface states density is observed for the n-type dry oxide samples.

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Current-Mode Deep Level Spectroscopy of Vanadium-Doped HPSI 4H-SiC

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1004.331 ◽

2020 ◽

Vol 1004 ◽

pp. 331-336

Author(s):

Giovanni Alfieri ◽

Lukas Kranz ◽

Andrei Mihaila

Keyword(s):

Deep Level Transient Spectroscopy ◽

Scientific Community ◽

Minority Carrier ◽

Deep Level ◽

Current Mode ◽

Low Energy ◽

The Other ◽

Carrier Trap ◽

Low Energy Electron ◽

Transient Spectroscopy

SiC has currently attracted the interest of the scientific community for qubit applications. Despite the importance given to the properties of color centers in high-purity semi-insulating SiC, little is known on the electronic properties of defects in this material. In our study, we investigated the presence of electrically active levels in vanadium-doped substrates. Current mode deep level transient spectroscopy, carried out in the dark and under illumination, together with 1-D simulations showed the presence of two electrically active levels, one associated to a majority carrier trap and the other one to a minority carrier trap. The nature of the detected defects has been discussed in the light of the characterization performed on low-energy electron irradiated substrates and previous results found in the literature.

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Deep levels in n-type Schottky and p+-n homojunction GaN diodes

MRS Internet Journal of Nitride Semiconductor Research ◽

10.1557/s1092578300005275 ◽

2000 ◽

Vol 5 (S1) ◽

pp. 922-928

Author(s):

A. Hierro ◽

D. Kwon ◽

S. A. Ringel ◽

M. Hansen ◽

U. K. Mishra ◽

...

Keyword(s):

Deep Level Transient Spectroscopy ◽

Minority Carrier ◽

Deep Level ◽

Schottky Diodes ◽

Yellow Luminescence ◽

Arrhenius Behavior ◽

Electron Level ◽

Transient Spectroscopy ◽

Electron And Hole Traps

The deep level spectra in both p+-n homojunction and n-type Schottky GaN diodes are studied by deep level transient spectroscopy (DLTS) in order to compare the role of the junction configuration on the defects found within the n-GaN layer. Both majority and minority carrier DLTS measurements are performed on the diodes allowing the observation of both electron and hole traps in n-GaN. An electron level at Ec−Et=0.58 and 0.62 V is observed in the p+-n and Schottky diodes, respectively, with a concentration of ∼3−4×1014 cm−3 and a capture cross section of ∼1−5×10−15 cm2. The similar Arrhenius behavior indicates that both emissions are related to the same defect. The shift in activation energy is correlated to the electric field enhanced-emission in the p+-n diode, where the junction barrier is much larger. The p+-n diode configuration allows the observation of a hole trap at Et−Ev=0.87 eV in the n-GaN which is very likely related to the yellow luminescence band.

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Z1/2- and EH6-Center in 4H-SiC: Not Identical Defects ?

Materials Science Forum ◽

10.4028/www.scientific.net/msf.717-720.251 ◽

2012 ◽

Vol 717-720 ◽

pp. 251-254 ◽

Cited By ~ 6

Author(s):

Bernd Zippelius ◽

Alexander Glas ◽

Heiko B. Weber ◽

Gerhard Pensl ◽

Tsunenobu Kimoto ◽

...

Keyword(s):

Activation Energy ◽

Electric Field ◽

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Schottky Contacts ◽

Double Peak ◽

Carbon Vacancy ◽

High Concentrations ◽

Transient Spectroscopy ◽

Dlts Spectra

Deep Level Transient Spectroscopy (DLTS) and Double-correlated DLTS (DDLTS) measurements have been conducted on Schottky contacts fabricated on n-type 4H-SiC epilayers using different contact metals in order to separate the EH6- and EH7-centers, which usually appear as a broad double peak in DLTS spectra. The activation energy of EH6(EC- ET(EH6) = 1.203 eV) turns out to be independent of the electric field. As a consequence, EH6is acceptor-like according to the missing Poole-Frenkel effect. Therefore, it can be excluded that the EH6-center and the prominent acceptor-like Z1/2-center belong to different charge states of the same microscopic defect as theoretically suggested. It is proposed that EH6is a complex containing a carbon vacancy and another component available at high concentrations. The activation energy of EH7(EC- ET(EH7) = 1.58 eV) has been evaluated indirectly by fitting the DLTS spectra of the EH6/7double peak taking the previously determined parameters of EH6into account.

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In Situ Deep Level Transient Spectroscopy of Defect Evolution in Silicon Following Ion Implantation at 80 K

MRS Proceedings ◽

10.1557/proc-532-73 ◽

1998 ◽

Vol 532 ◽

Cited By ~ 4

Author(s):

C. R. Cho ◽

R. A. Brown ◽

O. Kononchuk ◽

N. Yarykin ◽

G. Rozgonyi ◽

...

Keyword(s):

Deep Level Transient Spectroscopy ◽

Room Temperature ◽

Deep Level ◽

Temperature Range ◽

Type Silicon ◽

Defect Annealing ◽

Interstitial Defects ◽

Transient Spectroscopy ◽

Dlts Spectra

ABSTRACTThe evolution of defects in Czochralski and epitaxial p- and n-type silicon wafers following irradiation with He. Si or Ge ions at 80 K has been investigated by in situ deep level transient spectroscopy (DLTS). Defect annealing and formation reactions have been observed over the temperature range 80–350 K. In p-type silicon, new species-dependent levels are observed immediately after implantation, but these levels anneal out at or below room temperature. The wellknown divacancy and interstitial defects, usually reported after room temperature implantation, are revealed in the DLTS spectra only upon annealing at 160–200 K. In n-type silicon, vacancy-oxygen pairs are observed immediately after implantation. However, vacancy-related defects continue to form over a broad temperature range in samples implanted with Si or Ge. These observations are consistent with a model whereby vacancies and interstitials are released from defect clusters at temperatures >200 K to form divacancies and other defect pairs which are stable at room temperature.

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Characterisation of the Subthreshold Damage in MeV Ion Implanted p Si

MRS Proceedings ◽

10.1557/proc-510-411 ◽

1998 ◽

Vol 510 ◽

Author(s):

Shabih Fatima ◽

Jennifer Wong-Leung ◽

John Fitz Gerald ◽

C. Jagadish

Keyword(s):

Point Defects ◽

Deep Level Transient Spectroscopy ◽

Damage Evolution ◽

Peak Concentration ◽

Deep Level ◽

Extended Defects ◽

Transmission Electron ◽

Transient Spectroscopy ◽

P Type ◽

Dlts Spectra

AbstractSubthreshold damage in p-type Si implanted and annealed at elevated temperature is characterized using deep level transient spectroscopy (DLTS) and transmission electron microscopy (TEM). P-type Si is implanted with Si, Ge and Sn with energies in the range of 4 to 8.5 MeV, doses from 7 × 1012to 1×1014cm−2and all annealed at 800°C for 15 min. For each implanted specie, DLTS spectra show a transition dose called threshold dose above which point defects transform in to extended defects. DLTS measurements have shown for the doses below threshold, a sharp peak, corresponding to the signature of point defects and for doses above threshold a broad peak indicating the presence of extended defects. This is found to be consistent with TEM analyses where no defects are seen for the doses below threshold and the presence of extended defects for the doses above threshold. This suggests a defect transformation regime where point defects present below threshold are acting like nucleating sites for the extended defects. Also the mass dependence on the damage evolution has been observed, where rod-like defects are observed in the case of Si and (rod-like defects and loops) for Ge and Sn despite the fact that peak concentration of vacancies for Ge and Sn are normalized to the peak number of vacancies for Si.

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