GaAs monolithic microwave integrated circuit trimming using laser-direct-written tungsten microstrip lines

Laser-direct-write deposition of tungsten has been investigated as a technique for postfabrication trimming of GaAs monolithic microwave integrated circuits. Tungsten microstrip lines of 30 μΩ cm resistivity are deposited via a vapour-phase reaction induced by a focused argon-ion laser beam Lines of 1.8 μm thickness and 50μm width written on a semi-insulating GaAs substrate have a loss of 2.6 dB/cm at 16GHz. This trimming technique is proposed as a practical and accurate method for the optimisation of high-frequency GaAs circuits.