The role of the Eurasian badger (Meles meles) as a wildlife host has complicated the management of bovine tuberculosis (bTB) in cattle. Badger ranging behaviour has previously been found to be altered by culling of badgers and has been suggested to increase the transmission of bTB either among badgers or between badgers and cattle. In 2014, a five-year bTB intervention research project in a 100 km2 area in Northern Ireland was initiated involving selective removal of dual path platform (DPP) VetTB (immunoassay) test positive badgers and vaccination followed by release of DPP test negative badgers (‘Test and Vaccinate or Remove’). Home range sizes, based on position data obtained from global positioning system collared badgers, were compared between the first year of the project, where no DPP test positive badgers were removed, and follow-up years 2–4 when DPP test positive badgers were removed. A total of 105 individual badgers were followed over 21 200 collar tracking nights. Using multivariable analyses, neither annual nor monthly home ranges differed significantly in size between years, suggesting they were not significantly altered by the bTB intervention that was applied in the study area.

Brief meetings were held to confirm the elections of the incoming Division President, Francoise Genova and Vice President, Ray Norris along with the Organizing Committee which will consist of the incoming Presidents of the 7 Commissions (5,6,14,41,46,50 and 55) plus additional nominated members. The incoming Organizing Committee will thus consist of:

Division XII consists of Commissions that formerly were organized under the Executive Committee, that concern astronomers across a wide range of scientific sub-disciplines and provide interactions with scientists in a wider community, including governmental organizations, outside the IAU.

Recently it was reported that high quality, 10–100 μm thick, single-crystalline Si films were formed on oxidized single-crystalline Si wafers by the lateral epitaxial growth over oxide (LEGO) process. Although this recrystallization process is reliable and reproducible, periodic regions of dislocations in the otherwise relatively dislocation-free Si film were not well understood. In this paper, therefore, the film stress and defect properties are investigated in detail, and devices made in recrystallized wafers are compared with devices in conventional wafer structures. Stress levels were found to be too low to cause defects, with TEM data suggesting an impurity mechanism (SiO2 precipitation) for small dislocation loops and slight crystalline misorientation for long dislocation lines in the periodic, defective areas. Device results confirmed that LEGO is a viable alternative to the dielectric isolation (DI) technology.

The number of pages allocated to the commission report has been very limited and certainly not sufficient to cover in any exhaustive manner the wide range of topics relevant to cosmology and to provide also extensive bibliographies. Because of the vast amount of material to be covered, the report is based on a number of contributions from different colleagues who have been asked to highlight the main trends in the triennium (mid 1984 - mid 1987), together with a list of references sufficiently comprehensive to serve as a guideline for further reading. Unfortunately, two of the expected contributions did not reach me in time for inclusion in the report, and consequently topics such as the large scale structure and streaming motions, the clusters of galaxies and the counts of extragalactic radio sources are not included. However, it is my understanding that a large portion, if not all, of these topics will be covered in the reports of Commissions 28 and 40, and if true, this will at least avoid unnecessary overlaps. It should also be mentioned here that several proceedings of very recent IAU conferences provide excellent, updated and exhaustive reviews of the research work relevant to cosmology.

We have found that arsenic implanted into SiO2 segregates at high temperatures in an oxygen-free ambient into spherical, As-rich inclusions of 50 to 500A in diameter. The phase separation prevents diffusion of arsenic, even at temperatures as high as 1400 °C. However, the As-rich inclusions or droplets can be easily moved in a temperature gradient. They migrate towards the heat source at a rate of 2300A /hour in a gradient of 0.14 °C/μm, at 1405 °C, permitting their efficient removal from the oxide and into silicon. We propose a model to explain the dependence of droplet velocity on their size.

We have recently determined that anomalously low diffusion of high dose As implants in SiO2 is caused by phase separation. In an inert ambient, As segregates into spherical As-rich droplets of 50 to 500Å in diameter, which are essentially immobile when heated isothermally, even at 1405 °C. In a temperature gradient the droplets move toward the heat source.

The dependence of the segregation rate, drift, and diffusion on-the ambient and arsenic concentration is discussed here, and a new interpretation of the published arsenic diffusion data is provided.

We have developed a procedure to optimize electron mobility and leakage currents in MOSFETs fabricated in laser recrystallized polysilicon films on SiO2. A shaped laser beam was used to obtain grain boundaries aligned with the current flow in MOS transistors. To suppress grain boundary diffusion, rapid thermal annealing replaced all high temperature processing steps subsequent to source and drain implantation. By combining these two approaches, functional transistors as short as 1.5 μm were obtained, and also 2 μm-channel 19-stage ring oscillators with 115 psec/stage propagation delay.

During radiative melting, a silicon surface breaks up into coexisting solidand liquid regions with spacing dependent on incident flux, thermalparameters, and crystalline properties of the sample. The space-averagedreflectivity becomes a function of the incident photon flux, profoundlyaffecting the transfer of energy and the rate of melting.

We explain time evolution of the molten surface morphology and present datarelating depth of melting to the incident photon flux for bulk Si and Siwith buried oxide. The data prove the existence of a steady state transitionregion in which meltingis only superficial and time-independent.

Data are reported on short-channel MOSFET's fabricated in laser crystallized silicon-on-insulator (SOI) structures. In this experiment, special effort was made to minimize enhanced diffusion of dopants from the source and drain regions along grain boundaries. Instead of the standard anneal used for the implant activation, rapid thermal annealing and low temperature furnace annealing were used. These modified processes yielded functional MOSFET's with channel lengths as short as 1.5 μm, and ring oscillators of 2.0 μm. A speed of 115 ps per stage was obtained in these ring oscillators which is not only the fastest ever reported on any SOI structure, but also a factor of 2 faster than that from the same circuits in bulk Si. The results demonstrate quantitatively the speed improvement of SOI over bulk material due to reduced parasitic capacitance.

Dielectric Isolation (DI) technology has been available for almost twenty years. It was first developed for low capacitance, high speed circuits, and was later adapted to radiation hardened devices and for high voltage isolation. We describe a new method of forming DI structures that simplifies wafer fabrication, reduces the density of process induced defects, and may lead to a more flexible device design. Our process is based on recrystallization from the melt of thick Si films deposited over oxidized Si wafers, with a regular array of seeding windows opened in the isolation oxide. The recrystallized films are free of grain boundaries and subboundaries.

We report and analyze the breakup of a crystalline silicon surface into solid and molten faceted segments by radiative heating. Melting starts at discrete sites since there is a nucleation barrier requiring superheating of the surface. Once started, the melt remains localized and does not encompass the entire surface because of the changes in optical properties of Si upon melting. It is estimated that superheating by <0.5 K should be sufficient to stabilize faceted melt regions spaced 200 μm apart. The preliminary measurements, however, indicate superheating by several degrees.

Silicon can be prepared in a unique morphological form by anodic dissolution in HF. The resultant material contains pores of 10–100Å diameter in numbers sufficient toproduce a high surface area, low density single crystal. We have investigated the potential of both pulsed and CW laser processing in this material for dielectric isolation applications. Pulsed processing at λ = 532 nm yields fused surface layer structures that are epitaxial. The porous Si that underlies this surface film is undisturbed and can beoxidized to produce vertical isolation from the substrate.

Seeded epitaxial growth of Si over SiO2 is demonstrated in two types of structures. In the first case, rectangular pads of deposited Si were recessed into a thick SiO2 film. Narrow (≃ 5μm) via holes in SiO2 linked the pads with the bulk Si substrates. In the second embodiment, SiO2 patterns were recessed into the Si wafers which were then covered with a continuous 0.5μm poly-Si layer. In both cases, nearly planar geometries were maintained by use of local oxidation and etching techniques. Silicon was recrystallized with a focused Ar+ laser beam. Depending on the scanning conditions and the Si pattern geometry, single crystal growth propagated between 30 and >500μm. The factors influencing the extent and quality of the crystallized regions are discussed.

A high efficiency technique for incorporating As or other high volatility elements into Si and other semiconductors by laser pulse processing is described. By this method more than 80% of the As atoms painted onto a Si surface were made to relocate onto substitutional sites in the 73Si crystal. Mossbauer analysis of laser diffused As atoms in a Ge crystal indicates that although the final As sites are >97% substitutional, the majority are associated with one or more defects not seen in conventionally diffused material.

Grain boundary diffusion of arsenic and phosphorus in laser processed polycrystalline Si films has been investigated. Mesa diodes were fabricated in LPCVD Si thin films on SiO2 and subsequently recrystallized by cw Ar ion laser processing to form large grain material. The diffusion length of enhanced As and P diffusion along grain boundaries intersecting the p-n junction has been measured by the EBIC technique. Quantitative experimentation allowed determination of the grain boundary diffusion coefficients of As and P in the temperature range from 900°C to 1250°C.

Silicon layers evaporated on crystalline Si have been crystallized by Q-switched Nd:YAG laser irradiation. A strong correlation was observed between the density of a-Si films and the quality of the epitaxial regrowth from the liquid phase. Dense films crystallized epitaxially in a wide range of laser energy densities. Layers with 20% lower density, as determined by spectroscopic ellipsometry, had higher crystallization thresholds and suffered from severe pitting of the surface. Coalescence of the excess void volume into microbubbles, stabilized by gaseous contaminants, is responsible for the surface degradation.

In polycrystalline films on amorphous insulating substrates laser melting changes the grain distribution. Rapid melting and solidification of small diameter spots creates concentric rings of large crystallites. This characteristic pattern is explained by a simple model, based on the kinetics of crystallization.