One integrated circuit design calls for diffusing boron

Chapter 18, Problem 18.D5

(choose chapter or problem)

One integrated circuit design calls for diffusing boron into very highpurity silicon at an elevated temperature. It is necessary that at a distance 0.2 m from the surface of the silicon wafer, the room-temperature electrical conductivity be 1000 (#m)1 . The concentration of B at the surface of the Si is maintained at a constant level of 1.0 1025 m3 ; furthermore, it is assumed that the concentration of B in the original Si material is negligible, and that at room temperature, the boron atoms are saturated. Specify the temperature at which this diffusion heat treatment is to take place if the treatment time is to be 1 h. The diffusion coefficient for the diffusion of B in Si is a function of temperature as D(m2 >s) = 2.4 * 10-4 expa - 347,000 J>mol RT b S