Impurity diffusion induced by rapid thermal annealing (RTA) has been investigated for low energy B and BF2 implants in crystalline and preamorphized Si. A 50 keV 2×1015/cm2 Si self-implant was used for preamorphization. Samples were annealed with an oxide cap in an AG Associates HEATPULSE system (model 210T). Prior to the impurity depth profiling measurements, the SiO2 was removed with dilute HF. Significant B diffusion to theSiO2/Si interface was observed for a 1050°C/10 s anneal of 10 keV 3×1015/cm2 implanted;11B in crystalline and preamorphized Si. B interfacial concentrations were comparableto peak concentrations in unannealed samples. Diffusion of B and F to the SiO2/Si interface, and impurity gettering by ion straggling damage were observed for a 1050°C/10 s anneal of 45 keY 3×1O15/cm2 implanted 49BF2 in crystalline Si.though a loss F was apparent.

Depth profiles were determined with nuclear reaction analysis (NRA) [1-3], specifically the 11B(ρ,α0)8 Be(ER=163 key) [4] and 19F(ραγ)160 (ER - 340 keV) [5] reactions for 1lB and 19F profiling, respectively. This technique is sensitive to impurities at or near the surface and can reveal impurity diffusion to near-surface regions not usually detectable with secondary ion mass spectrometry (SIMS). NRA depth profiling has shownthat RTA can result in significant impurity diffusion to the SiO2/Si interface for B implanted in crystalline and preamorphized Si, and BF2 implanted in crystalline Si. Impurity concentrations at the interface are estimated to be in excess of 1020/cm3 for the implantation and annealing conditions used in this report. BF2 implanted in preamorphized Si showed greatly reduced impurity concentrations at the interface. A knowledge of the impurity concentrations at the substratesurface or the SiO2/Si interface becomes increasingly important as device dimensions decrease. Matrix effects make such measurements difficult with SIMS.

Rapid thermal annealing (RTA) of shallow Sb-implanted Si has been studied with Rutherford Backscattering Spectrometry (RBS). Single crystal Si wafers were implanted with Sb at energies of 16, 32 and 48 keV and doses of 5×1014 and 1×1015/cm2. RTA and reference furnace anneals in a nitrogen atmosphere were done to activate the dopant and remove implantation damage. Glancing-angle RBS measurements were used to determine the Sb depth distributions. Dopant profiles obtained with RBS analysis were compared with Secondary Ion Mass Spectrometry results and TRIM code calculations. RBS measurements of the projected range and range straggle did not differ significantly from TRIM code calculations. Following annealing, significant Sb diffusion from the as-implanted peak was apparent. Sb accumulation at the substrate surface was pronounced, especially for furnace-annealed samples.

The interface between ultrathin sputtered lead zirconate titanate (PZT) films and a conductive electrode (indium tin oxide-ITO) is investigated. Structural and compositional changes at the PZT-ITO interface have been examined by surface analysis and depth profiling techniques of glancing angle X-ray diffraction, Rutherford backscattering (RBS), SIMS, Auger electron spectroscopy (AES), and elastic recoil detection analysis (ERDA). Studies indicate significant interdiffusion of lead into the underlying ITO layer and glass substrate with a large amount of residual stress at the interface. Influence of such compositional deviations at the interface is correlated to an observed thickness dependence in the dielectric properties of PZT films.

Epistles 8.14, one of Pliny's longest letters, has been widely dismissed as a clumsy combination of two ill-fitting stretches of prose. This article demonstrates a significant chain of allusions in the letter's opening to Tacitus’ Agricola, as well as to Cicero, Ovid and Seneca; it shows how Pliny prompts such a reading in the surrounding Epistles 8.13 and 8.15; and, through consideration of the diptych form and the theme of slavery, it demonstrates the letter's pivotal role as centrepiece to Book 8.

Psoroptes ovis, the causative agent of sheep scab, is an important ectoparasitic mite infecting sheep, goats and cattle. Infection is characterized by an extensive dermatitis, scab formation and intense itching. Initial focal lesions spread outwards, coalesce and may extend over the whole body. The host response to infestation has all the characteristics of an immediate-type hypersensitivity reaction but the mite antigens and allergens which initiate this response are almost completely undefined. Here, 507 randomly selected cDNAs derived from a mixed population of P. ovis were sequenced and the resultant nucleotide sequences subjected to Cluster analysis and Blast searches. This analysis yielded 280 clusters of which 49 had >1 sequence with 24 showing significant Blast X homology to another protein in the databases. There were 231 sequences which appeared on one occasion and 109 of these showed significant Blast X homology to other sequences in the databases. This analysis identified homologues of 9 different types of allergens which have been characterized in other allergic conditions such as responses to house dust mites. It also identified a number of cysteine proteases which may contribute to lesion development as well as several free-radical scavenging enzymes which may protect the mite from host immune effector responses.