Characterization of Iron and Its Nitride Nanoparticles Prepared by CVC Process without Using a Chiller

Iron and its nitride (e-Fe3N) nanoparticles were fabricated by the CVC using Fe(CO)5 precursor without the aid of LN2 chiller. The iron particles synthesized at 400 oC were a mixture of amorphous and crystalline a-Fe. Fully crystallized iron particles were then obtained above 600 oC. Iron-nitride particles that were easily formed at 500 oC at 1 atm., however, were not fully developed in vacuum unless the reaction temperature reached 850 oC. Nevertheless, the work chamber needed to be maintained in vacuum to obtain finer iron-nitride particles. The synthesized particles possessing the core-shell type structure were all nearly spherical and enclosed with Fe3O4 or Fe3O4-related amorphous layer. The iron nanoparticles (~20 nm) synthesized at 600 oC at 760 torr exhibited iHc ~ 1.0 kOe and Ms ~ 170 emu/g, whereas the iron-nitride particles (~20 nm) synthesized at 850 oC at 0.01 torr exhibited iHc ~ 0.45 kOe and Ms ~ 115 emu/g.

In-Situ Use of an Optical Microscope for FIB Microsurgery of Planarized Devices

The extensive use of planarization in many of today's leading process technologies significantly reduces the effectiveness of FIB circuit modification and debugging. Planarization has played a significant role in the development of denser chips with increasingly smaller geometries. Fully planarized devices offer little or no surface features on which the FIB operator relies for orientation and alignment. These conditions lead to increased debug cycle times and decreased success rates using the FIB. Recent FIB tool advancements in the field of C4 (controlled-collapse chip connection) flip-chip packaged device modification and debug have also made it easier to work on highly planarized conventional wire-bond technology. The integration of an optical microscope with an infrared camera into the work chamber allows the operator to view the circuitry under the surface layer. This paper will offer several techniques for overcoming the challenges that planarized devices present by using this in-situ optical microscope. When properly implemented, these techniques can significantly improve the success rate and throughput time of device modification on highly planarized parts.

Precision Ion Polishing System -A New Instrument for TEM Specimen Preparation of Materials

The article describes the design, construction and performance of a new bench top instrument for high speed ion beam thinning and polishing of materials. In this system, the combination of very low angle ion milling and powerful ion guns has led to the rapid production of high quality TEM specimens. The main subassemblies are (1) a work chamber (2) gas control system (3) vacuum system and (4) electrical system. The work chamber consists of a pair of newly designed Penning type ion guns and Faraday cups to measure ion currents. The Whisperlok™ mechanism provides specimen rotation, pneumatically driven airlock for very fast specimen exchange and transmission/reflection illumination for specimen viewing. The ion guns are mounted to deliver a nominal, 4° milling angle on the specimen surface with precision alignment of ±2° about horizontal and vertical axes. The actual thinning is undertaken from one side using a single, post-type specimen holder which minimizes the specimen heating and contamination. The ion beam current of each gun can be individually optimized by varying the flow rate of the ionizing gas. The main chamber is evacuated by diaphragm and molecular drag pumps to produce a clean, dry vacuum in the 10−6 Torr range. The discharge and accelerating voltages required for the operation of each gun are provided by a dual high voltage power supply capable of delivering ion energies in the range; 1 keV to 6keV. TEM micrographs of typical ion polished specimens of semiconductors, metals, ceramics and composites are included to illustrate the performance of the instrument.