In situ four-point conductivity and Hall effect apparatus for vacuum and controlled atmosphere measurements of thin film materials

An ultrahigh vacuum (UHV) chamber equipped with a fixture for in situ four-point Van Der Pauw conductivity and Hall effect measurements has been constructed and attached to a multichamber thin film synthesis and characterization system. The combined systems allow for film synthesis and characterization of microstructure, chemical composition, morphology, and electronic transport properties without air exposure. The four-point measurement fixture features spring-loaded probes for electrical contacts and temperature measurement and a sample docking mechanism designed to minimize probe damage to the films. The electronics were designed for measurement of high resistance samples. Measurements can be made at sample temperatures from 25 to 450 degreesC in selected gas environments from UHV to atmospheric pressure. The design and performance of the system are reported, and representative results on the electronic transport properties of n-type Si (100) and tungsten oxide films on sapphire are presented. (C) 2002 American Institute of Physics.