Ion implantation of GaAs integrated circuits

The conditions required for the fabrication of low pinch-off voltage MESFETs by ion implantation have been established. Calculation of the device characteristics from measured carrier concentration profiles has shown that a Vp of -1.5V is best achieved using low implant energies together with ion doses of 2 x 1012 cm-2. Characterisation of the implant and annealing conditions has enabled the implanted dose to be corrected for the activation after annealing. Measurement of the processed devices has shown the variation in saturation current to be as low as 3 mA over 75% of the wafer area, showing suitability for use in logic circuit fabrication. (author)