CONTACTLESS MEASUREMENT OF SHEET CARRIER CONCENTRATION AND MOBILITY OF THIN LAYERS ON SEMI-INSULATING GaAs.

A method has been developed which measures the reflection coefficient of a thin conducting layer on a semi-insulating wafer and its change in a static magnetic field. From this the sheet resistance and magnetoconductive mobility are found. This method is contactless, non-destructive, absolute and fast. The sample is mounted across a waveguide so as to permit the wafer to physically exceed the guide dimensions. Layers have been measured at 300 and 85K with good agreement with Hall measurements. Heterojunction layers have also been measured.