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Microinductors were fabricated using electrodeposition for integration on semiconductor substrates. The process was optimised through validated models developed to focus on efficiency and footprint. Lithographic processing was performed to microfabricate Cu coils over a magnetic core. A racetrack design was used to maximise the high frequency response, yielding high inductance density and low DC resistance. The magnetic core was subsequently closed using a magnetic thin film deposition over a dielectric deposited on the Cu coils. Homogeneous ferromagnetic alloy, Ni45Fe55 of uniform thickness over a high aspect-ratio 3D structure has been achieved. Ni45Fe55 was chosen for the fabrication of micromagnetic cores due to its relatively high saturation flux density (1.6 T), resistivity (48 mΩ cm) and anisotropy field (9.5 Oe). The rationale, design, microfabrication process and characterisation results are presented.

In this paper the authors discuss the issues surrounding the formation of ultrashallow n-type junctions in Ge. In general the n-type dopants are relatively difficult to activate and diffuse quickly, leading to high access resistances and limited capability to reduce the device dimensions, respectively. Sheet resistance (Rs) was calculated for n-type box-like profiles in Si and Ge. To achieve ITRS Roadmap targets in Si an active doping concentration of 1.5-2×1020 cm-3 is required, but due to the enhanced electron mobility it is predicted approximately 6×1019 cm-3 is sufficient in Ge.

(100) germanium wafers were patterned by e-beam lithography with various exposure doses, in combination with dry etch, resulting in fin structures with widths in the range of approximately 20-150 nm with a high aspect ratio, running in either the [100] or [110] direction. Fins were also subjected to various anneals in N2 to examine germanium desorption but little or no size reduction was observed for realistic thermal budgets. Other samples received a phosphorus implant (at 7°) that partially amorphized the structures. The amorphous depth was 120 nm. Subsequently a 400 °C 3 min furnace anneal in N2 recrystallized the wide fins completely, leading to the formation of various defects, including twin boundaries, small localized defects, and stacking faults. Recrystallization was retarded in narrow fins as was reported in silicon fins.

Titanates exhibit electronic properties highly desirable for field effect transistors such as very high permittivity and ferroelectricity. However, the difficulty of chemically etching titanates hinders their commercial use in device manufacturing. Here, the authors report the selective area in finestra growth of highly crystalline BaTiO3 (BTO) within photolithographically defined openings of a sacrificial SiO2 layer on a Ge (001) wafer by molecular beam epitaxy. After the BaTiO3 deposition, the sacrificial SiO2 can be etched away, revealing isolated nanoscale gate stacks circumventing the need to etch the titanate thin film. Reflection high-energy electron diffraction in conjunction with scanning electron microscopy is carried out to confirm the crystallinity of the samples. X-ray diffraction is performed to determine the out-of-plane lattice constant and crystal quality of the BTO film. Electrical measurements are performed on electrically isolated Pt/BaTiO3/SrTiO3/Ge capacitor devices.Titanates exhibit electronic properties highly desirable for field effect transistors such as very high permittivity and ferroelectricity. However, the difficulty of chemically etching titanates hinders their commercial use in device manufacturing. Here, the authors report the selective area in finestra growth of highly crystalline BaTiO3 (BTO) within photolithographically defined openings of a sacrificial SiO2 layer on a Ge (001) wafer by molecular beam epitaxy. After the BaTiO3 deposition, the sacrificial SiO2 can be etched away, revealing isolated nanoscale gate stacks circumventing the need to etch the titanate thin film. Reflection high-energy electron diffraction in conjunction with scanning electron microscopy is carried out to confirm the crystallinity of the samples. X-ray diffraction is performed to determine the out-of-plane lattice constant and crystal quality of the BTO film. Electrical measurements are performed on electrically isolated Pt/BaTiO3/SrTiO3/Ge capacitor devices.

All existing transistors are based on the use of semiconductor junctions formed by introducing dopant atoms into the semiconductor material. As the distance between junctions in modern devices drops below 10 nm, extraordinarily high doping concentration gradients become necessary. Because of the laws of diffusion and the statistical nature of the distribution of the doping atoms, such junctions represent an increasingly difficult fabrication challenge for the semiconductor industry. Here, we propose and demonstrate a new type of transistor in which there are no junctions and no doping concentration gradients. These devices have full CMOS functionality and are made using silicon nanowires. They have near-ideal subthreshold slope, extremely low leakage currents, and less degradation of mobility with gate voltage and temperature than classical transistors.

The authors investigate F as a non-dopant co-implant to suppress P and As diffusion in Ge. F was placed either overlaying the dopant profile, or deeper to counteract the influence of end-of-range defects, which is a common ultra-shallow junction optimization approach in Si substrates. It was determined that F outgasses extremely quickly from Ge, as a 1×1015cm−2 implanted dose escaped completely during a rapid thermal anneal as short as 1 sec, at 600 °C. This behavior is attributed to rapid diffusion, instability of F-defect clusters, and an aversion of F to reside substitutionally in the Ge lattice. The F diffusivity at 600 °C is in the order of some metal impurity diffusivities at that temperature.

We report the fabrication of junctionless SOI MOSFETs. Such devices greatly simplify processing thermal budget and behave as regular multigate SOI transistors.

Producción Científica, The authors investigate the templated crystallization of thin-body Ge fin structures with high aspect ratios. Experimental variables include fin thickness and thermal treatments, with fin structures oriented in the 〈110〉 direction. Transmission electron microscopy determined that various crystal defects form during crystallization of amorphous Ge regions, most notably {111} stacking faults, twin boundaries, and small crystallites. In all cases, the nature of the defects is dependent on the fin thickness and thermal treatments applied. Using a standard 600 °C rapid-thermal-anneal, Gestructures with high aspect ratios crystallize with better crystal quality and fewer uncured defects than the equivalent Si case, which is a cause for optimism for thin-film Ge devices., Science Foundation Ireland under Research Grant Nos. 09/SIRG/I1623 and 09/SIRG/I1621.

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Design and optimization of n-type doped regions in germanium by solid phase epitaxial recrystallization (SPER) have been studied by the authors. A systematic study is presented of process variables that influence activation and thermal stability, including preamorphization, coimplants, recrystallization temperature, and postrecrystallization thermal treatments. Unlike silicon, activation after recrystallization in germanium is not optimum where the postrecrystallization thermal budget is kept to a minimum. With the aid of modeling, a maximum peak activation of 7 X 10(19) cm(-3) was extracted. A steady increase in sheet resistance during postrecrystallization anneals confirms the formation of metastable activation by SPER. It is predicted that active concentrations of 6-8 X 10(19) cm(-3) are sufficient to meet targets for sub-20 nm technologies. (C) 2010 American Institute of Physics. (doi: 10.1063/1.3452345)

Gold acetylide compounds [(R3P)AuC[triple bond]CC(Me)(OH)Et], where R = Ph 1 or cyclohexyl (Cy) 2, were synthesised and 2 was characterised using X-ray diffraction techniques. The solid-state structure of 2 contained a two-coordinate gold atom and a linear P-Au-C[triple bond]C-C bonding sequence. The reactions between 1 or 2 and [NR4][nido-7,8-As2B9H10] or [NR4][nido-7-TeB10H10] in ethanol-acetone solvent afforded the twelve-vertex cluster species [NMe4][3-(R3P)-closo-3,1,2-AuAs2B9H9], where R = Ph 5 or Cy 6, or [NEt4][3-(R3P)-closo-2,1-AuTeB10H10], where R = Ph 7 or Cy 8, in moderate or low yields (ca. 35% for , and and ca. 20% for ). Compounds and were characterised with X-ray crystallographic techniques. Although there was crystallographic disorder in the {As2B3} and {TeB4} rings to which the gold atoms were attached, the structures of 5 and 7 strongly suggested that the gold atoms were pentahapto bonded to all the atoms in the {As2B3} or {TeB4} rings giving formally closo cluster geometries with closo cluster electron counts. The solution-phase NMR properties of 5, 6 and 7 were consistent with closo descriptions.