Nondestructive mapping of GaAs wafers from measurement of magnetoresistance effect using a novel microwave device

A novel electrical technique for mapping GaAs wafers by using a microwave cell with nondestructive capacitive contacts is proposed. A numerical analysis is performed to calculate the magnetoelectric effects. For large samples such as wafers, it shows that the magnetoresistance effect is much more important than the Hall effect. The values of the sheet resistance (R_□), the mobility (μ_H) and the sheet density (n_S) of the free carriers are obtained from two resistance measurements (with magnetic field B=0 and B=1 T). These determinations only necessitate one apparatus factor whose value is obtained from a calibration performed once for all. Results concerning superficial or buried layers and heterostructures are presented