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Characterisation of Single Ion Tracks for use in Ion Beam LithographyAlves, Andrew David Charles, aalves@unimelb.edu.au January 2008 (has links)
To investigate the ultimate resolution in ion beam lithography (IBL) the resist material poly(methyl methacrylate) PMMA has been modified by single ion impacts. The latent damage tracks have been etched prior to imaging and characterisation. The interest in IBL comes from a unique advantage over more traditional electron beam or optical lithography. An ion with energy of the order of 1 MeV per nucleon evenly deposits its energy over a long range in a straight latent damage path. This gives IBL the ability to create high aspect ratio structures with a resolution in the order of 10 nm. Precise ion counting into a spin coated PMMA film on top of an active substrate enabled control over the exact fluence delivered to the PMMA from homogenously irradiated areas down to separated single ion tracks. Using the homogenous areas it was possible to macroscopically measure the sensitivity of the PMMA as a function of the developing parameters. Separated single ion tracks wer e created in the PMMA using 8 MeV F, 71 MeV Cu and 88 MeV I ions. These ion tracks were etched to create voids in the PMMA film. For characterisation the tracks were imaged primarily with atomic force microscopy (AFM) and also with scanning electron microscopy (SEM). The series of studies presented here show that the sensitivity of the resist-developer combination can be tailored to allow the etching of specific single ion tracks. With the ability to etch only the damage track, and not the bulk material, one may experimentally characterise the damage track of any chosen ion. This offers the scientific community a useful tool in the study and fabrication of etched ion tracks. Finally work has been conducted to allow the precise locating of an ion beam using a nanoscale mask and piezoelectrically driven scanning stage. This method of beam locating has been trailed in conjunction with single ion detection in an effort to test the practical limits of ion beam lithography in the single ion realm.
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Strukturierte NV-Qubits durch hochaufgelöste räumlich-selektive EinzelionenimplantationRaatz, Nicole 02 September 2021 (has links)
Hochaufgelöste räumlich-selektive Einzelionenimplantation ist eine Schlüsseltechnologie um Festkörper-Qubits herzustellen. Der in dieser Arbeit verwendete Nanoimplanter benutzt zur Kollimation eines niederenergetischen Ionenstrahls auf Nanometerebene eine Rasterkraftmikroskop-(AFM-)Spitze, welche mit einer Nanoapertur ausgestattet ist. Diese Technik wurde bereits für verschiedene Quantenanwendungen genutzt. In dieser Arbeit wird sie auf die Erzeugung strukturierter Stickstoff-Fehlstellen-(NV-)Zentren weiterentwickelt und optimiert. Dies umfasst unter anderem die Installation eines neuen AFM-Systems, welches den Aufbau mit zwei nützlichen Funktionen aufrüstet: die In-situ-Aperturvermessung und die Untersuchung von Ionen-sensitiven Fotolacken. Weiter werden die zwei wichtigsten limitierenden Faktoren der räumlichen Auflösung durch Simulationen und Experimente detailliert untersucht. Die Ergebnisse geben Aufschluss über optimale Nanoaperturen und Implantationsbedingungen. Streueffekte an der AFM-Spitze und Gitterführungen in Diamant können dadurch maßgeblich reduziert werden. Weiter werden NV-limitierende Effekte durch mehrere Ausheizschritte sowie Ionen- und Elektronenbestrahlungen untersucht. Zuletzt
werden erstmals diamantbasierte Ionendetektoren hergestellt, welche mit Kapazität- und Strom-Spannungs-Messungen, durch Röntgenbestrahlung und Ionenstrahl-induzierter Ladung (IBIC) charakterisiert werden. Die Ergebnisse zeigen, dass die angefertigten Detektoren die Bedingungen für eine deterministische Implantation erfüllen, so dass dieses Prinzip zukünftig in den Nanoimplanter integriert werden kann. / High-resolution spatial-selective single ion implantation is a key technology to produce solid state qubits. The nanoimplanter used in this work collimates a low-energy ion beam at the nanometer level using an atomic force microscope (AFM) tip, which is provided with a nanoaperture. This technique has already been used for various quantum applications. In this thesis it is further developed and optimized for the generation of structured nitrogen vacancy (NV) centers. This includes the installation of a new AFM system, which upgrades the setup with two useful functions: in-situ aperture measurement and the investigation of ion sensitive photoresists. Furthermore, the two most significant limiting factors of spatial resolution are studied in detail by simulations and experiments. The results indicate optimized nanoapertures and implantation conditions. Scattering effects at the AFM tip and ion channeling in diamond can be significantly reduced. Moreover, NV-limiting effects are investigated by several heating steps as well as ion and electron irradiations. Finally, novel diamond based ion detectors are manufactured, that are characterized by capacitance and current-voltage measurements, by X-ray irradiation and ion beam induced charge (IBIC). The results show these detectors fulfill the conditions for a deterministic implantation, so that this concept can be integrated into the nanoimplanter in the future.
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