2.) Copper is a typical interconnect (effectively, a metal wire between devices) material. In a new MOSFET design, Cu will be in direct contact with the pure Si substrate. If it diffused into the active area of the device, Cu atoms could destroy device performance. At standard operating conditions, due to resistive heating, a device will generally operate at 70C. a.) If the concentration of Cu on the Si surface is held constant at 6.001015cm3, how long will it take for the bulk concentration of Cu in the wafer to become 1013cm3 at a depth of 1m and hence destroy the device? Note: in a computer, we want these devices to last 3 years or 109 seconds. (b.) Repeat for an Al interconnect (common before the mid-1990s). You should find that Al diffusion will not be a limiting factor in device lifetime