Doping to Create a Semiconductor: Changing Conductive Properties by Diffusion

In the semiconductor industry scientists take advantage of diffusion to; dope or introduce atoms into a silicon wafer to change its conductive properties. The lesson simulates the diffusion of a gas phase substance (ammonia) into a solid substrate (gelatin); and compares the lab model of diffusion to the doping process of silicon wafers. Students will examine how diffusion occurs and explore how the electrical properties of semiconductors are developed. This lesson uses only commonly available substances.