Influence of the Ge Dose in Ion-implanted SiO2 Layers on the Related Nanocrystal-memory Properties

2006 ◽  
Vol 933 ◽  
Author(s):  
Sébastien Duguay ◽  
Jean-Jacques Grob ◽  
Abdelilah Slaoui ◽  
Philippe Kern
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silicon Dioxide ◽  
Rutherford Backscattering Spectrometry ◽  
Implantation Dose ◽  
Oxide Semiconductor ◽  
Transmission Electron ◽  
Germanium Nanocrystals ◽  
Nanocrystal Memory ◽  
Displacement Per Atom

ABSTRACTThin silicon dioxide (SiO2) on Si layers with embedded germanium nanocrystals (Ge-ncs) were fabricated using 74Ge+-implantation at 15 keV and subsequent annealing. Transmission electron microscopy and Rutherford backscattering spectrometry have been used to study the Ge redistribution in the SiO2 films as a function of implantation dose under specific annealing conditions. At low implantation doses, Germanium is found to segregate at the Si/SiO2 interface leading to poor electrical properties. At higher doses and when the disorder limit of one displacement per atom is reached at the interface, transmission electron microscopy revealed the formation of a Ge-nc layer array located close to the Si/SiO2 interface and an another one inside the SiO2 host material. This near-interface high density (>1012 ncs/cm2) nc-layer is found to act as a floating gate embedded within the silicon dioxide. Capacitance-voltage measurements performed on metal-oxide-semiconductor structures containing such implanted SiO2 layers show significant memory properties (few volts hysteresis) at low programming voltages (<|10V|) due to the presence of Ge-ncs near the Si/SiO2 interface

Dechannealing Study of Nanocrystalline Si:H Layers Produced by High Dose Hydrogen Irradiation of Silicon Crystals

1998 ◽  
Vol 536 ◽  
Author(s):  
V. P. Popov ◽  
A. K. Gutakovsky ◽  
I. V. Antonova ◽  
K. S. Zhuravlev ◽  
E. V. Spesivtsev ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Rutherford Backscattering Spectrometry ◽  
Nanocrystalline Structure ◽  
Structural Defects ◽  
High Dose ◽  
Silicon Crystals ◽  
Strong Energy ◽  
Transmission Electron ◽  
Hydrogen Implantation

AbstractA study of Si:H layers formed by high dose hydrogen implantation (up to 3x107cm-2) using pulsed beams with mean currents up 40 mA/cm2 was carried out in the present work. The Rutherford backscattering spectrometry (RBS), channeling of He ions, and transmission electron microscopy (TEM) were used to study the implanted silicon, and to identify the structural defects (a-Si islands and nanocrystallites). Implantation regimes used in this work lead to creation of the layers, which contain hydrogen concentrations higher than 15 at.% as well as the high defect concentrations. As a result, the nano- and microcavities that are created in the silicon fill with hydrogen. Annealing of this silicon removes the radiation defects and leads to a nanocrystalline structure of implanted layer. A strong energy dependence of dechanneling, connected with formation of quasi nanocrystallites, which have mutual small angle disorientation (<1.50), was found after moderate annealing in the range 200-500°C. The nanocrystalline regions are in the range of 2-4 nm were estimated on the basis of the suggested dechanneling model and transmission electron microscopy (TEM) measurements. Correlation between spectroscopic ellipsometry, visible photoluminescence, and sizes of nanocrystallites in hydrogenated nc-Si:H is observed.

Post Oxidation Anneal and Re-Oxidation Effects in 5 nm SiO2 Films

1986 ◽  
Vol 76 ◽  
Author(s):  
L. Dori ◽  
M. Arienzo ◽  
Y. C. Sun ◽  
T. N. Nguyen ◽  
J. Wetzel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silicon Dioxide ◽  
Oxygen Vacancies ◽  
Interface Roughness ◽  
Cross Sectional ◽  
Oxide Charge ◽  
Transmission Electron ◽  
Redistribution Of Hydrogen ◽  
Transmission Electron Microscopy Cross

ABSTRACTUltrathin silicon dioxide films, 5 nm thick, were grown in a double-walled furnace at 850°C in dry O2. A consistent improvement in the electrical properties is observed following the oxidation either with a Post-Oxidation Anneal (POA) at 1000°C in N2 or with the same POA followed by a short re-oxidation (Re-Ox) step in which 1 nm of additional oxide was grown. We attribute these results to the redistribution of hydrogen and water related groups as well as to a change in the concentration of sub-oxide charge states at the Si-SiO2 interface. A further improvement observed after the short re-oxidation step had been attributed to the filling of the oxygen vacancies produced during the POA. High resolution Transmission Electron Microscopy cross-sectional observations of the Si-iSO2 interface have evidenced an increase in the interface roughness after the thermal treatment at high temperature. These results are in agreement with recent XPS data.

Defects in Germanium Nanocrystals Produced by Ion Implantation

2013 ◽  
Vol 709 ◽  
pp. 148-152
Author(s):  
Yu Juan Zhang ◽  
Lei Shang
Keyword(s):  
Electron Microscopy ◽  
Light Emission ◽  
Stacking Faults ◽  
Implantation Dose ◽  
Defect Structures ◽  
High Temperature Annealing ◽  
Planar Defects ◽  
Transmission Electron ◽  
Microstructural Defects ◽  
Germanium Nanocrystals

Germanium nanocrystals (Ge-nc) were produced by the implantation of Ge+ into a SiO2 film deposited on (100) Si, followed by a high-temperature annealing. High-resolution transmission electron microscopy (HRTEM) has been used to investigate the defect structures inside the Ge-nc produced by different implantation doses (1×1016, 2×1016, 4×1016 and 8×1016 cm-2). It has been found that the planar defects such as nanotwins and stacking faults (SFs) are dominant in Ge-nc (60%) for the samples with implantation doses higher than 2×1016 cm-2, while for the sample with an implantation dose lower than 1×1016 cm-2, fewer planar defects are observed in the Ge-nc (20%). The percentages of nanotwins in the planar defects are 87%, 77%, 67% and 60% in four samples, respectively. The twinning structures include single twins, double twins and multiple twins. We also found that there are only SFs in some nanocrystals, and in others the SFs coexist with twins. These microstructural defects are expected to play an important role in the light emission from the Ge-nc.

Factors affecting Ge nanocrystal size in co-sputtered Ge+SiO2films

2000 ◽  
Vol 638 ◽  
Author(s):  
WK Choi ◽  
V Ng ◽  
YW Ho ◽  
TB Chen ◽  
V Ho
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Thermal Processing ◽  
Rapid Thermal Processing ◽  
Annealing Duration ◽  
Factors Affecting ◽  
Transmission Electron ◽  
Germanium Nanocrystals ◽  
Ge Nanocrystals

AbstractThe high resolution transmission electron microscopy and Raman spectroscopy results of germanium nanocrystals embedded in SiO2 synthesized by rapid thermal processing (RTA) have been presented. From the results of samples with different Ge concentrations, it was concluded that there is a narrow window in the Ge concentration that can produce nanocrystals. We also showed that it is possible to vary RTA duration or temperature to produce Ge nanocrystals with varying sizes. Our results therefore suggest that it is possible to utilize (i) annealing duration and; (ii) temperature to tune crystal sizes for optoelectronic applications.

Wet Oxidation of Si1-x-yGexCy Layers on (100) Si

1995 ◽  
Vol 398 ◽  
Author(s):  
A. E. Bair ◽  
Z. Atzmon ◽  
T. L. Alford ◽  
D. Chandrasekhar ◽  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Oxidation Behavior ◽  
Rutherford Backscattering Spectrometry ◽  
Reference Sample ◽  
Oxide Growth ◽  
Wet Oxidation ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Content Alloy

ABSTRACTSingle crystal Si0.63Ge0.36C0.01 and amorphous Si0.65Ge0.27C0.08 layers have been oxidized in a wet ambient at 700 °C and 900 °C. The oxide growth has been studied using Rutherford backscattering spectrometry and transmission electron microscopy. A reference sample of Si0.63Ge0.37 was also oxidized in order to determine the influence of C on the oxidation behavior. The lower C content alloy behaved similar to the SiGe alloy. Uniform Si1-xGexO2 was obtained at 700 °C whereas SiO2 was formed at 900 °C, and Ge piled up underneath the oxide. In both cases, C was not detected in the oxide layer. The amorphous Si0.65Ge0.27C0.08 alloy behaved significantly different at both oxidation temperatures in comparison with the crystalline Si0.63Ge0.36C0.01 and Si0.63Ge0.37. Negligible oxidation occurred at 700 °C whereas SiO2 was obtained at 900 °C and the rejected Ge distributed uniformly throughout the SiGeC alloy. It is proposed that fast Ge diffusion during oxidation at 900 °C resulted from diffusion at grain boundaries, since crystallization of the amorphous SiGeC layer occurred in conjunction with oxidation, leading to nucleation of ∼5 nm nanocrystals.

Ion implantation in β-SiC: Effect of channeling direction and critical energy for amorphization

1988 ◽  
Vol 3 (2) ◽  
pp. 321-328 ◽  
Author(s):  
J. A. Edmond ◽  
R. F. Davis ◽  
S. P. Withrow ◽  
K. L. More
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Computer Program ◽  
Liquid Nitrogen ◽  
Cross Section ◽  
Damage Accumulation ◽  
Room Temperature ◽  
Critical Energy ◽  
Implantation Dose ◽  
Transmission Electron

Damage in single-crystal β-SiC(100) as a result of ion bombardment has been studied using Rutherford backscattering/channeling and cross-section transmission electron microscopy. Samples were implanted with Al (130 keV) and Si (87 keV) with doses between 4 and 20 × 1014 cm−2 at liquid nitrogen and room temperatures. Backscattering spectra for He+ channeling as a function of implantation dose were initially obtained in the [110] direction to determine damage accumulation. However, the backscattered yield along this direction was shown to be enhanced as a result of uniaxial implantation-induced strain along [100]. Spectra obtained by channeling along this latter direction were used along with the computer program TRIM to calculate the critical energy for amorphization. The results for amorphization of β-SiC at liquid nitrogen and room temperature are ∼ 14.5 eV/atom and ∼ 22.5 eV/atom, respectively.

Formation of Defect Clusters in SrTiO3 Crystals Implanted with Xenon Ions

2007 ◽  
Vol 561-565 ◽  
pp. 1757-1760 ◽  
Author(s):  
Ming Hui Song ◽  
Xing Jian Guo ◽  
Nobuhiro Ishikawa ◽  
Masaki Takeguchi ◽  
Kazutaka Mitsuishi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Point Defects ◽  
Crystalline State ◽  
Implantation Dose ◽  
Defect Clusters ◽  
Other Point Defects ◽  
Transmission Electron ◽  
Post Implantation

SrTiO3 crystals were implanted with 100 keV xenon (Xe+) ions at 673 or 1073 K up to 2.0 × 1020 ions m−2. Defect clusters formed in the ion-implanted samples were investigated with conventional and high-resolution transmission electron microscopy. Nanometer-sized clusters were formed in the samples. The clusters grew large in size after post-implantation annealing and with increasing the implantation dose. The clusters were faceted with {100}, or {110} of SrTiO3. Though the nano-sized clusters were expected to contain Xe atoms, they were not in crystalline state. The results suggest that even if the clusters contain Xe atoms, they also contain other point defects such as vacancies.

RBS, TEM and SEM Characterization of Gold Nanoclusters in TiO2(110)

2003 ◽  
Vol 792 ◽  
Author(s):  
V. Shutthanandan ◽  
Y. Zhang ◽  
C. M. Wang ◽  
J. S. Young ◽  
L. Saraf ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Rutherford Backscattering Spectrometry ◽  
Gold Nanoclusters ◽  
Subsequent Annealing ◽  
Transmission Electron ◽  
Scanning Electron

ABSTRACTNucleation of gold nanoclusters in TiO2(110) single crystal using ion implantation and subsequent annealing were studied by Rutherford backscattering spectrometry /channeling (RBS/C), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Approximately 1000 Au2+/nm2 were implanted at room temperature in TiO2(110) substrates. TEM and SEM measurements reveal that rounded nanoclusters were formed during the implantation. In contrast, subsequent annealing in air for 10 hours at 1275 K promoted the formation of faceted (rectangular shaped) Au nanostructures in TiO2. RBS channeling measurements further reveled that Au atoms randomly occupied the host TiO2 lattice during the implantation. However, it appears that some Au atoms moved to the Ti lattice positions after annealing.

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