The relationship between the resistivity of semi-insulating GaAs and MESFET properties

The combination of time domain charge measurement (TDCM) and scanning photoluminescence (sPL) has been used to characterize the wafer-scale and device-scale variations in the resistivity of the semi-insulating GaAs substrates used in MESFET manufacture. Samples from more than 150 boules of commercial grade semi-insulating (SI) GaAs from a number of vendors using different growth techniques and post-growth annealing procedures were studied. The relationship between substrate resistivity and MESFET properties was studied by showing how substrate resistivity changes during device processing and demonstrating how it affects ion implant activation efficiency and the saturated source drain current in finished devices.