The objective of this Web site is twofold: (1) to describe the Hall measurement technique for determining the carrier density and mobility in semiconductor materials and (2) to initiate an electronic interaction forum where workers interested in the Hall effect can exchange ideas and information. The following pages will lead the reader through an introductory description of the Hall measurement technique, covering basic principles, equipment, and recommended procedures.
The importance of the Hall effect is supported by the need to determine accurately carrier density, electrical resistivity, and the mobility of carriers in semiconductors. The Hall effect provides a relatively simple method for doing this. Because of its simplicity, low cost, and fast turnaround time, it is an indispensable characterization technique in the semiconductor industry and in research laboratories. Furthermore, two Nobel prizes (1985, 1998) are based upon the Hall effect.
The history of the Hall effect begins in 1879 when Edwin H. Hall discovered that a small transverse voltage appeared across a current-carrying thin metal strip in an applied magnetic field. Until that time, electrical measurements provided only the carrier density-mobility product, and the separation of these two important physical quantities had to rely on other difficult measurements. The discovery of the Hall effect enabled a direct measure of the carrier density. The polarity of this transverse Hall voltage proved that it is in fact electrons that are physically moving in an electric current. Development of the technique has since led to a mature and practical tool, which today is used routinely for characterizing the electrical properties and quality of almost all of the semiconductor materials used by industry and in research labs throughout the world.