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Depth resolved positron annihilation measurements were carried out on 85?keV and 1?MeV nitrogen ion implanted InP samples. The defect sensitive S-parameter and R-parameter values for the low energy implantations confirm the presence of monovacancies up to a dose of 1015?cm?2 and coexistence of monovacancies and divacancies for 1016?cm?2 dose sample. Corroborative glancing incidence x-ray diffraction measurements on the highest dose sample revealed that the sample is amorphized. For high energy implantation, it is found that vacancy-defects are present right from the near-surface region and these defects are identified to be monovancancies, based on the observed S- and R-parameters. A comparison of the results for the low and high energy implantations is made.

The transformation of Pd/Si to Pd2Si/Si is studied using Auger electron spectroscopy over a wide temperature range of 370–1020 K. The Pd film gets totally converted to Pd2Si upon annealing at 520 K, and beyond 570 K, Si starts segregating on the surface of silicide. It is found that the presence of surface oxygen influences the segregation of Si. The time evolution study of Si segregation reveals that segregation kinetics is very fast and the segregated Si concentration increases as the temperature is increased. Scanning electron microscopy measurements show that Pd2Si is formed in the form of islands, which grow as the annealing temperature is increased.

In spite of the large amount of tribological work carried out to explain the friction and wear mechanism in diamond-like carbon (DLC) films, some of the core issues relating to the evolution of reactive species across sliding interfaces and their role on the friction and wear mechanism remain unclear. The phase composition, film density and hydrogen content present in a DLC film can be tailored by substrate biasing during film deposition to achieve a nearly vanishing friction coefficient. Furthermore, nitrogen doping in DLC films significantly improves wear resistance, and sliding occurs in a nearly wearless regime. Undoped and nitrogen-doped DLC films exhibit a nearly frictionless value with ultra-low wear behavior when tests are performed in argon, nitrogen and methane atmospheres. The antifriction and antiwear properties of the DLC films were improved with the reduction of adsorbed oxygen impurities on the film surface. This behavior was understood by correlating the oxygen impurities present at the surface/subsurface region of the DLC film while using x-ray photoelectron spectroscopy and depth-resolved Auger electron spectroscopy.

Depth-resolved positron annihilation studies have been carried out on nitrogen-implanted Si to investigate defect evolution and thermal stability. Si(1 0 0) wafers have been implanted with 60 keV N+ ions to a fluence of 1 × 1014 and 1 × 1015 ions/cm2. From positron diffusion analysis of defect-sensitive S-parameter profiles, it is found that the higher dose sample undergoes a two-step annealing process consisting of annealing of deep level defects, followed by vacancy agglomeration near the surface at 873 K. For the low dose sample, however, nitrogen vacancy complexes are the only major defects remaining at 873 K. Annealing at 1073 K is sufficient to remove all kinds of open volume defects present in the samples.