2,584 research outputs found
Nitrogen Implantation and Diffusion in Crystalline Germanium: Implantation Energy, Temperature and Ge Surface Protection Dependence
No full textIn the present work nitrogen (N2+) has been implanted in crystalline germanium at a constant dose and its diffusion has been studied as a function of implantation energy, annealing temperature and various capping layers deposited on substrate surface. Nitrogen diffusion in germanium appears to be, as in the case of silicon, anomalous toward the capping layer/germanium interface not obeying the second Fick’s law. In addition, it appears independent on the capping layer composition. As the implantation energy increases, characteristic nitrogen pileups appear in the region beyond the former amorphous/crystalline interface, attributed to the formation of nitrogen-Ge point defects (in particular interstitials) clusters. There is an evidence that N diffusion in Ge is related to the presence of Ge interstitials gradients maintained during post-implantation annealing between the capping layer/Ge interface and the region
beyond the former amorphous/crystalline interface of the substrate. This unique diffusion behavior of N could find applications in Ge based MOS (Metal-Oxide-Semiconductor) technology as proposed in the body of the present article
Diffusion of implanted nitrogen in germanium.
No full textIn the present work diffusion of implanted nitrogen in
germanium is studied as a function of implantation energy
and post-implantation annealing temperature. Implantations
have been performed at a constant dose and
energies leading to the amorphization of the substrate.
Nitrogen diffusion in Ge is anomalous (not obeying the
2nd Fick’s law) towards the substrate surface on which an
Al2O3 layer has been deposited before annealing for protection.
There is evidence that N diffusion in Ge is interstitial-
assisted and takes place in the presence of Ge interstitials
gradients between the Al2O3/Ge and the former
amorphous/crystalline (a/c) interface of the substrate during
annealing
Post-metallization annealing and photolithography effects in p-type Ge/Al 2 O 3 /Al MOS structures
No full textIn this work, the combined effect of negative tone photolithography and post-metallization annealing (PMA) on the electrical behavior of Al/Al2O3/p-Ge MOS structures are investigated. During photoresist development, the exposed upper part of the Al2O3 film weakens due to the reaction with the developer. Subsequent processes of Al deposition and PMA at 350 °C result in alumina thickness reduction. The gate electrode formation seems to involve at least three processes: (a) germanium substrate out-diffusion and accumulation at the top of the alumina layer that takes place during the alumina deposition, (b) alumina destabilization, and (c) germanium diffusion into the deposited Al metal and Al diffusion into the alumina. The overall effect is the reduction of the alumina thickness due to its partial consumption. It is shown that the germanium diffusion depends on the annealing duration, and not on the annealing ambient (inert or forming gas). Although PMA passivates interface traps near the valence band edge, the insulating properties of the stacks are degraded. This degradation appears as a low-level ac loss, attributed to a hopping current that flows through the Al2O3 layer. The results are discussed and compared to recently reported on Pt/Al2O3/p-Ge structures formed and treated under the same conditions
Stoquastic Hamiltonians and the Monte Carlo sign problem
No full textMasters Thesis on the Monte Carlo sign problem and stoquastic Hamiltonians
Author: Marios Ioannou
Supervisor: Prof. Barbara Terha
Phosphorous Diffusion in N2+ -Implanted Germanium during Flash Lamp Annealing: Influence of Nitrogen on Ge Substrate Damage and Capping Layer Engineering
No full textIn this work we present a systematic study on post-implantation phosphorous diffusion control in Ge by co-implanted nitrogen in combination with various surface capping layers (Al2O3, SiO2 and Si3N4). Phosphorous has been implanted at low energy (11 keV) and high dose (1015 cm−2) in p-Ge (100) already implanted or not with low energy (10 keV−5 × 1014 cm−2) N2+. Flash Lamp Annealing (FLA) at 800–850°C for 20 ms in inert ambient has been used as post-implantation annealing scheme. In the absence of nitrogen, significant substrate damage and capping layer deterioration prevents a reliable comparison among the three capping materials. The presence of nitrogen in the Ge substrate, effectively suppresses the damage observed after the FLA. In this case, P diffusion is additionally retarded in the presence of Al2O3 as compared to SiO2 and Si3N4. The experimental results constitute a direct evidence of the action of the three capping layers as sinks for Ge vacancies with different interface recombination velocities. On the contrary, the nitrogen diffusion data suggest that interface recombination velocities of Ge interstitials are almost independent of the capping layer choice
High performance n +/p and p +/n germanium diodes at low-temperature activation annealing
No full textIn this work we demonstrate the fabrication and characterization of high performance junction diodes using annealing temperatures within the temperature range of 300–350 C. The low temperature dopant activation was assisted by a 50 nm platinum layer which transforms into platinum germanide during
annealing. The fabricated diodes exhibited high forward currents, in excess of 400 A/cm2 at |0.7| V for both p+/n and n+/p diodes, with forward to reverse ratio IF/IR greater than 104. Best results for the n+/p junctions were obtained at the lower annealing temperature of 300 C. These characteristics compare favorably with the results of either conventional or with Ni or Co assisted dopant activation annealing. The low-temperature annealing in combination with the high forward currents at low bias makes this method suitable for high performance/low operating power applications, utilizing thus high mobility germanium substrates
Strong Diffusion Suppression of Low Energy-Implanted Phosphorous in Germanium by N2 Co-Implantation
No full textIn this work an effective diffusion suppression of low energy – high dose (11 keV, 1E15 cm−2) phosphorous in 10 keV/5 × 1E14cm−2 N2+ -implanted p- germanium is demonstrated. Diffusion of both species after isochronal 30 sec RTA annealing at 550–650◦C has been studied by SIMS in the presence of Al2O3 as surface capping layer. Nitrogen shows anomalous non-Fickian diffusion towards the Al2O3/Ge interface, while phosphorous dose loss and diffusion to the bulk are strongly suppressed in comparison to Ge substrate without nitrogen implantation. Possible physical mechanisms (involving phosphorous-vacancies or phosphorous-nitrogen complexes, and end-of-range interstitials) that explain this result are presented and discussed
La Shoah à Salonique dans l’œuvre de l’écrivain Georges Ioannou
No full textSalonique est la ville grecque qui a le plus souffert de la Shoah. Longtemps surnommée « la Jérusalem des Balkans », la capitale historique de la Macédoine grecque est devenue presque judenrein à la fin de l’Occupation. Dans l’œuvre de Georges Ioannou (1927-1985), l’un des plus grands prosateurs de la Grèce d’après-guerre, la Shoah occupe une place particulière, parce que l’auteur est hanté par les fantômes du passé. Dans les pages qui suivent, le lecteur pourra lire deux des sept textes écrits par Ioannou sur son expérience de témoin de la Shoah à Salonique.Salonika is the Greek town that suffered the most from the Holocaust. Called “the Balkans Jerusalem” for a long time, the historical main town of Greek Macedonia is almost “judenrein” at the end of the German occupation. In the work of George Ioannou (1927-1985), one of the most important prose writer of Post-War Greece, the Holocaust has a special place because the author is haunted by ghosts from the past. In the following pages, the reader will discover two of the seven texts written by Ioannou, as witness, from his own experience of the Holocaust in Salonika.Η Θεσσαλονίκη είναι η ελληνική πόλη η οποία περισσότερο υπέφερε από το Ολοκαύτωμα. Αυτή που ονομάστηκε η «Ιερουσαλήμ των Βαλκανίων» βρέθηκε «άνευ Ιουδαίων» στο τέλος της γερμανικής κατοχής. Στο έργο του Γιώργου Ιωάννου [1927-1985], ο οποίος υπήρξε ένας από τους πιο σημαντικούς πεζογράφους της μεταπολεμικής Ελλάδας, το Ολοκαύτωμα κατέχει μια ιδιαίτερη θέση, καθώς τα φαντάσματα του παρελθόντος στοιχειώνουν τον συγγραφέα. Στις παρακάτω σελίδες ο αναγνώστης θα διαβάσει δύο από τα επτά κείμενα τα οποία ο Ιωάννου, μάρτυρας του Ολοκαυτώματος στην Θεσσαλονίκη, έγραψε από την προσωπική του εμπειρία
The Significance of a Fast-Track EVAR Procedure: It's Not the Years in Your Life That Count, It's the Life in Your Years
No full text
- …
