Mining in Cornwall and Devon tin was found as alluvial deposits of cassiterite in the gravels of stream beds. Eventually tin was mined underground; underground mines sprang up as early as the 16th century. Tin lodes were also found in outcroppings of cliffs. Tin is one of the earliest metals to have been exploited in Britain. Chalcolithic metal workers discovered that by putting a small proportion of tin (5 – 20%) in molten copper, the alloy bronze was produced. The alloy is harder than copper. The oldest production of tin-bronze is in Turkey about 3500 BC, but exploitation of the tin resources in Britain is
Copper interconnect is to use Cu-Ge alloy as the interconnect material so that buffer layer (e.g. TiN) is no longer needed. Epitaxial CuGe layer has been fabricated with an average resistivity of 6 ± 1 μΩ cm and work function of ~4.47 ± 0.02 eV respectively, qualifying it as a good alternative to Cu. Resistance to electromigration, the process by which a metal conductor changes shape under the influence of an electric current flowing through it and which eventually leads to the breaking of the conductor, is significantly better with copper than with aluminium. This improvement in electromigration resistance allows higher currents