Reduction of Secondary Defects in High Energy O-Implanted Si by High Energy Si Irradiation

1992 ◽  
Vol 279 ◽  
Author(s):  
S. L. Ellingboe ◽  
M. C. Ridgway
Keyword(s):  
High Temperature ◽  
Defect Structure ◽  
Low Dose ◽  
Defect Formation ◽  
Volume Fraction ◽  
High Energy ◽  
High Dose ◽  
High Temperature Annealing ◽  
Before And After ◽  
Secondary Defect

ABSTRACTThe effect of 4.2 MeV, low dose Si irradiation before annealing of 1 MeV, high dose O-implanted Si has been studied. Si irradiation results in differences in the defect structure both before and after high temperature annealing. With no Si irradiation, annealing results in polycrystalline Si (polySi) formation and microtwinning at the front SiO2/Si interface. With Si irradiation, the polySi volume fraction is greatly reduced after annealing, twinned Si having grown in its place. Si irradiation has no effect on Si inclusions within the SiO2 layer. The dependence of secondary defect formation on Si dose and implant temperature is presented. In particular, Si irradiation at low implant temperatures (150°C) and moderate doses (5×1016 cm−2) is shown to be most effective in the reduction of the polySi volume fraction at the front SiO2/Si interface.

Evolution and Future Trends of SIMOX Material

MRS Bulletin ◽  
1998 ◽  
Vol 23 (12) ◽  
pp. 25-29 ◽  
Author(s):  
Steve Krause ◽  
Maria Anc ◽  
Peter Roitman
Keyword(s):  
High Temperature ◽  
Low Power ◽  
High Speed ◽  
New Technologies ◽  
Low Voltage ◽  
Semiconductor Industry ◽  
High Energy ◽  
Silicon On Insulator ◽  
High Dose ◽  
High Temperature Annealing

Oxygen-implanted silicon-on-insulator (SOI) material, or SIMOX (separation by implantation of oxygen), is another chapter in the continuing development of new material technologies for use by the semiconductor industry. Building integrated circuits (ICs) in a thin layer of crystalline silicon on a layer of silicon oxide on a silicon substrate has benefits for radiationhard, high-temperature, high-speed, low-voltage, and low-power operation, and for future device designs. Historically the first interest in SIMOX was for radiation-hard electronics for space, but the major application of interest currently is low-power, high-speed, portable electronics. Silicon-on-insulator also avoids the disadvantage of a completely different substrate such as sapphire or gallium arsenide. Formation of a buried-oxide (BOX) layer by high-energy, high-dose, oxygen ion implantation has the advantage that the ion-implant dose can be made extremely precise and extremely uniform. However the silicon and oxide layers are highly damaged after the implant, so high-temperature annealing sequences are required to restore devicequality material. In fact SIMOX process development necessitated the development of new technologies for high-dose implantation and high-temperature annealing.

Defect reduction in oxygen implanted silicon-on-insulator material during high-temperature annealing

1989 ◽  
Vol 47 ◽  
pp. 604-605
Author(s):  
P. Roitman ◽  
B. Cordts ◽  
S. Visitserngtrakul ◽  
S.J. Krause
Keyword(s):  
High Temperature ◽  
Annealing Temperature ◽  
Silicon On Insulator ◽  
High Dose ◽  
High Temperature Annealing ◽  
High Current ◽  
Defect Reduction ◽  
Annealing Step ◽  
Multiple Cycle ◽  
Defect Densities

Synthesis of a thin, buried dielectric layer to form a silicon-on-insulator (SOI) material by high dose oxygen implantation (SIMOX – Separation by IMplanted Oxygen) is becoming an important technology due to the advent of high current (200 mA) oxygen implanters. Recently, reductions in defect densities from 109 cm−2 down to 107 cm−2 or less have been reported. They were achieved with a final high temperature annealing step (1300°C – 1400°C) in conjunction with: a) high temperature implantation or; b) channeling implantation or; c) multiple cycle implantation. However, the processes and conditions for reduction and elimination of precipitates and defects during high temperature annealing are not well understood. In this work we have studied the effect of annealing temperature on defect and precipitate reduction for SIMOX samples which were processed first with high temperature, high current implantation followed by high temperature annealing.

Benefit/Risk Profile of Combined Antiplatelet Therapy with Ticlopidine and Aspirin

1991 ◽  
Vol 65 (05) ◽  
pp. 504-510 ◽  
Author(s):  
Raffaele De Caterina ◽  
Rosa Sicari ◽  
Walter Bernini ◽  
Guido Lazzerini ◽  
Giuliana Buti Strata ◽  
...  
Keyword(s):  
Platelet Function ◽  
Low Dose ◽  
Bleeding Time ◽  
Ex Vivo ◽  
Stable Coronary Artery Disease ◽  
High Dose ◽  
Single Drug ◽  
Before And After ◽  
Serum Thromboxane ◽  
Artery Disease

SummaryTiclopidine (T) and aspirin (ASA) are two antiplatelet drugs both capable of prolonging bleeding time (BT), with a different mechanism of action. A synergism in BT prolongation has been reported and is currently considered an argument for not recommending their combination. However, a profound suppression of platelet function might be a desirable counterpart of a marked prolongation of BT, with a possible use in selected clinical situations. We therefore studied ex vivo platelet function (aggregation by ADP 0.5-1-2.5 μM; adrenaline 0.75-2.5 μM; collagen 1.5-150 μg/ml; arachidonic acid 1 mM; PAF 1 μM; adrenaline 0.17 μM + ADP 0.62 μM; serum thromboxane ([TX]B2 generation) and BT (Mielke) in 6 patients with stable coronary artery disease receiving such combination. Patients underwent sequential laboratory evaluations at baseline, after 7 days of T 250 mg b.i.d., before and after the intravenous administration of ASA 500 mg, respectively, and, finally, after a minimum of 7 days of sole ASA oral administration (50 mg/day). The experimental design, therefore, allowed a comparison of T and ASA effects (2nd and 4th evaluation), and an assessment of the combination effect (3rd evaluation). Platelet aggregation in response to all doses of ADP was depressed more by T than by ASA. Conversely, responses to adrenaline, and arachidonate were affected more by ASA than by T. For all other agents, differences were not significant. T + ASA combination was more effective (p <0.05) than either treatment alone in depressing responses to high-dose collagen (% over control, mean ± SEM: T: 95 ± 3; ASA: 96 ± 5; T + ASA: 89 ± 4). Serum TXB2 (basal, ng/ml: 380 ± 54) did not change with T (372 ± 36), dropped to <1 ng/ml on ASA injection and slightly re-increased to 9.1 ± 3.1 ng/ml on oral low-dose ASA. BT (basal 7.4 ± 0.6 min) was affected similarly by T (9.2 ± 0.8) or ASA (9.7 ± 0.9) alone, but increased to 15.0 ± 0.7 min on combination treatment (106% increase over control). Thus, the strong synergism in BT prolongation by ASA-T combination has a counterpart in the inhibition of platelet function in response to strong stimuli such as high-dose collagen, not otherwise affected significantly by single-drug treatment. This effect is a possible rationale for the clinical evaluation of T + ASA combination.

A New Hafnium-Beryllium System Prioduced by Ion Implantation and Annealing Techniques

1983 ◽  
Vol 27 ◽  
Author(s):  
J.C. Soares ◽  
A.A. Melo ◽  
M.F. DA Silva ◽  
E.J. Alves ◽  
K. Freitag ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Single Crystals ◽  
Room Temperature ◽  
Low Dose ◽  
Correlation Method ◽  
High Dose ◽  
Tetrahedral Sites ◽  
Time Differential ◽  
Before And After ◽  
Beryllium Foil

ABSTRACTLow and high dose hafnium imolanted beryllium samoles have been prepared at room temperature by ion implantation of beryllium commercial foils and single crystals. These samples have been studied before and after annealing with the time differential perturbed angular correlation method (TDPAC) and with Rutherford backscattering and channeling techniques. A new metastable system has been discovered in TDPAC-measurements in a low dose hafnium implanted beryllium foil annealed at 500°C. Channeling measurements show that the hafnium atoms after annealing, are in the regular tetrahedral sites but dislocated from the previous position occupied after implantation. The formation of this system is connected with the redistribution of oxygen in a thin layer under the surface. This effect does not take place precisely at the same temperature in foils and in single crystals.

Suppression of SiC surface roughening during high-temperature annealing by atmospheric control using purified Ar gas

2010 ◽  
Vol 25 (4) ◽  
pp. 708-710 ◽  
Author(s):  
Atsushi Ogura ◽  
Daisuke Kosemura ◽  
Shingo Kinoshita
Keyword(s):  
Surface Roughness ◽  
High Temperature ◽  
Surface Roughening ◽  
Annealing Atmosphere ◽  
High Temperature Annealing ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Furnace Tube ◽  
Ar Gas

4H-silicon carbide (SiC) wafers were annealed at 1300 and 1600 °C for 30 min and 60 min in a conventional and purified Ar atmosphere. The surface roughness before and after annealing was evaluated by atomic force microscopy. The surface roughness before annealing was approximately 2.37 nm in root mean square. The roughness, after annealing for 30 min at 1300 and 1600 °C in a conventional Ar furnace, was increased to 4.53 and 14.9 nm, respectively. The roughness, after annealing for 60 min, was 5.01 and 19.1 nm, respectively. In this study, the G3 grade Ar gas (99.999%) was supplied in the conventional furnace tube. When the Ar gas was purified to an impurity concentration of less than 1 ppb, and it was supplied in the leak-tight furnace tube, the roughness after 30-min annealing improved 4.27 and 6.93 nm at 1300 and 1600 °C, respectively. The roughness after 60-min annealing was also reduced to 3.54 and 9.28 nm, respectively. We assume that a significant reduction of H2O concentration in the annealing atmosphere might play an important role in suppressing surface roughening of SiC during high-temperature annealing.

Observation of Shrinking and Reformation of Shockley Stacking Faults by PL Mapping

2006 ◽  
Vol 527-529 ◽  
pp. 375-378 ◽  
Author(s):  
Toshiyuki Miyanagi ◽  
Hidekazu Tsuchida ◽  
Isaho Kamata ◽  
Tomonori Nakamura ◽  
R. Ishii ◽  
...  
Keyword(s):  
High Temperature ◽  
Laser Irradiation ◽  
High Power ◽  
Stacking Faults ◽  
High Temperature Annealing ◽  
High Power Laser ◽  
Power Laser ◽  
Before And After ◽  
Basal Plane Dislocation ◽  
Pl Mapping

We provide evidence of shrinking of Shockley-type stacking faults (SSFs) in the SiC epitaxial layer by high temperature annealing. Photoluminescence (PL) mapping in combination with high-power laser irradiation makes it possible to investigate the formation of SSFs, which lie between a pair of partial dislocations formed by dissociation of a basal plane dislocation (BPD), without fabrication of pin diodes. Using this technique, we investigated the annealing effect on SSFs. Comparing before and after annealing at 600°C for 10 min, it became obvious that high-temperature annealing results in shrinking of the faulted area of the SSFs. The SSFs form into the same features as those before annealing when high-power laser irradiation is performed again on the same area. This result shows that the faulted area of SSFs shrinks by 600°C annealing but the nuclei of SSFs (BPDs) do not disappear.

Aluminum-Ion Implantation into 4H-SiC (11-20) and (0001)

2004 ◽  
Vol 815 ◽  
Author(s):  
Y. Negoro ◽  
T. Kimoto ◽  
H. Matsunami
Keyword(s):  
High Temperature ◽  
Sheet Resistance ◽  
Room Temperature ◽  
Dose Dependence ◽  
High Dose ◽  
High Temperature Annealing ◽  
Aluminum Ion ◽  
Hall Effect Measurements ◽  
Short Time ◽  
Surface Morphologies

AbstractHigh-dose aluminum-ion (Al+) implantation into 4H-SiC (11-20) and (0001) has been investigated. Surface morphologies of implanted (0001) samples were improved by annealing with a graphite cap. Implant-dose dependence and annealing-time dependence of electrical properties are examined by Hall-effect measurements. A low sheet resistance of 2.3 kΩ/sq. was obtained in (0001) by high-dose Al+ implantation at 500 °C with a dose of 3.0 × 1016 cm−2 and high-temperature annealing at 1800 °C for a short time of 1 min. In the case of (11-20), even room-temperature implantation brought a low sheet resistance below 2 kΩ/sq. after annealing at 1800 °C.

Effect of insulin on regional vascular resistances in conscious rats

1996 ◽  
Vol 270 (2) ◽  
pp. R450-R455
Author(s):  
E. Qadir ◽  
J. P. Porter
Keyword(s):  
Skeletal Muscle ◽  
Arterial Pressure ◽  
Low Dose ◽  
Chronic Administration ◽  
High Dose ◽  
Ganglionic Blockade ◽  
Conscious Rats ◽  
Before And After ◽  
Vascular Beds ◽  
Renal Vascular

In the rat, but not in humans and other mammals, chronic administration of insulin produces hypertension. The present aim was to determine the effect of acute insulin infusion on regional vascular resistances and to determine the neurogenic contribution to the response. Conscious rats were infused with insulin (2 or 6 mU/min) before and after ganglionic blockade with chlorisondamine (5 mg/kg). The low dose of insulin produced an increase in arterial pressure and hindquarter vascular resistance; the high dose produced a gradual decrease in arterial pressure and renal resistance. After ganglionic blockade, the hindquarter vasoconstriction produced by the low dose was abolished. The high dose of insulin produced both hindquarter and renal vasodilation. Thus the low dose of insulin had a selective neurogenic vasoconstrictor effect in rat skeletal muscle vascular beds. With higher doses, direct vasodilatory effects in both skeletal muscle and renal vascular beds appeared. This greater sensitivity of the sympathoexcitatory effects of insulin in rats may explain the ability of chronic insulin infusions to increase blood pressure in this species.

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