The Characteristics of Very Shallow Silicon Junctions

Previous investigations have shown that the characteristics of shallow diffused junctions frequently exhibit important departures from those predicted by the ordinary solutions of the diffusion equation. These characteristics depend on the details of diffusion processes and play an important, but not completely understood, role in establishing detector quality. For example, the resolution loss associated with the junction deadlayer is generally greater than that predicted by simple statistics. This paper reports the results of a series of investigations undertaken for the purpose of optimizing the properties of detector junctions. Junctions studied have ranged in depth from 0.75 micron to several angstroms (estimated). Diffusion methods and junction structure are discussed. In addition, a rapid method for determining the details of junction structure by electronic scanning is described.