Selector device for the determination of the type of electroconductivity in semiconductor wafers

Claim 1

A selector device for the determination of the type of electroconductivity in a semiconductor wafer utilizing the polarity of the electromotive force produced in the semiconductor wafer by the Hall effect, said device comprising first and second pairs of probes in a diagonal arrangement to be contacted with the surface of the semiconductor wafer under measurement, one of said pairs of probes supplying an electric current through the wafer, and the other of said pairs of probes detecting the electromotive force produced in the wafer by the Hall effect, and a pair of permanent magnets opposed to each other with a gap in which the semiconductor wafer to be measured is placed when under measurement, one of said permanent magnets being positioned within the circumference determined by said probes, wherein said one of said permanent magnets positioned within the circumference determined by said probes has dimensions such as to be confined within the circle or ellipse inscribed to a square or rhombus having corners at the contact points between said probes and the surface of the semiconductor wafer under measurement.