Infrared flash annealing for fabricating GaAs MESFET´s

GaAs ion-implanted layers for GaAs MESFET´s have been successfully annealed by several seconds radiation from halogen lamps without any encapsulants. Si-implanted GaAs (5 × 10¹²cm^-2, 100 keV)for an active layer annealed at 950°C for 2 seconds shows 40-50 % electrical activation with no signs of thermal dissociation. High carrier concentration profiles for S-implanted n⁺layers formed by this technique are also achieved with only slight impurity diffusion during annealing. For confirming the applicability of the annealing method, MESFET´s with 1 µm gate length and 300 µm gate width were fabricated on the active layer formed by this technique. They show 20-30 % higher transconductance than that for MESFET´s fabricated on conventional furnace annealed active layer. The higher transconductance is explained by steeper carrier concentration profile with higher peak carrier concentration in the active layer annealed by this method.