Suppose a finite surface source containing both phosphorus and lithium atoms is applied to the surface of a silicon wafer. Ten times as much P is present as Li and a diffusional anneal is carried out...

Suppose a finite surface source containing both phosphorus and lithium atoms is applied to the surface of a silicon wafer. Ten times as much P is present as Li and a diffusional anneal is carried out at 1200°C for 5 hours. After codiffusion, at what distance beneath the wafer surface will the concentration of P equal that of Li?