3 3 The AwSi phase diagram is shown below. This sys- tem has importance in the semiconductor industry wherever Au contacts are deposited on Si circuit sub- strates. (a) Identify the phase or phases associated with each area of the diagram. (6) What would happen if one tried to melt gold in a silicon crucible? (c) Assuming that Au and Si follow the freezing. point depression expression, and find A Heves AHS for each element from the observed eutec- tic temperature and composition. 1600 1400 1404 'C 1200 1063 °C 1 1000 7/C - 800 1 600 370 °C 400 200 Au 0.? 0.4 0.6 0.3 Si . Au X Si