A high aspect-ratio 0.1 micron gate technique for low-noise MESFET´S

A new technique, using optical lithography, has been developed to produce very thick submicron gates. This technique has produced Al gates 900Å long and 1.7µm thick, for an aspect-ratio (gate thickness/gate length) of ∼ 19. Using this high aspect-ratio gate structure, GaAs MESFET´s have been fabricated with gate lengths as short as 0.1µm and widths as wide as 300µm. Gate resistances of 17Ω/mm and 37Ω/mm of gate width have been measured for half-micron and quarter-micron long Al gates, respectively.