ABSTRACT
The selectively changing of electrical properties of silicon through the introduction of impurities commonly referred to as dopants. Substitutional diffusion mechanism is applicable to the most common diffusants, such as B, P and As. Substitutional diffusion happens when a substitutional atom exchanges lattice positions with a vacancy-requires the presence of a vacancy. Interstitial diffusion occurs when an interstitial atom jumps to another interstitial position. During interstitial diffusion the diffusing atom jumps from one interstitial position to another interstitial position, with relatively low barrier energy and a relatively high number of interstitial sites. One factor is the rapid diffusion of the impurity through the oxide and escape into the ambient. This will depend on the diffusivity of the impurity in the oxide. Diffusion of impurities into a semiconductor slice being treated as a 1-dimensional problem is valid since the horizontal dimensions are much larger than the vertical diffusion depth.
